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xmlns="http://www.w3.org/2000/svg" class="icon timer-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="timer icon" name="timer"><path d="M799.387 122.15c4.402-2.978 7.38-7.897 7.38-13.463v-1.165c0-8.933-7.38-16.312-16.312-16.312H256.33c-8.933 0-16.311 7.38-16.311 16.312v1.165c0 5.825 2.977 10.874 7.637 13.592 4.143 194.44 97.22 354.963 220.201 392.763-122.204 37.542-214.893 196.511-220.2 389.397-4.661 5.049-7.638 11.651-7.638 19.03v5.825h566.49v-5.825c0-7.379-2.849-13.981-7.509-18.9-5.049-193.016-97.867-351.985-220.2-389.527 123.24-37.67 216.446-198.453 220.588-392.892zM531.16 450.445v352.632c117.674 1.553 211.787 40.778 211.787 88.676H304.097c0-48.286 95.149-87.382 213.728-88.676V450.445c-93.077-3.107-167.901-81.297-167.901-177.093 0-8.803 6.99-15.793 15.793-15.793 8.803 0 15.794 6.99 15.794 15.793 0 80.261 63.69 145.635 142.01 145.635s142.011-65.374 142.011-145.635c0-8.803 6.99-15.793 15.794-15.793s15.793 6.99 15.793 15.793c0 95.019-73.789 172.82-165.96 177.093z"></path></svg><span>About 19 min</span><meta property="timeRequired" content="PT19M"></span><!----><!----></div><hr></div><!----><div class="" vp-content><!----><div id="markdown-content"><h1 id="data-modeling" tabindex="-1"><a class="header-anchor" href="#data-modeling"><span>Data Modeling</span></a></h1><h2 id="_1-database-management" tabindex="-1"><a class="header-anchor" href="#_1-database-management"><span>1. Database Management</span></a></h2><h3 id="_1-1-create-database" tabindex="-1"><a class="header-anchor" href="#_1-1-create-database"><span>1.1 Create Database</span></a></h3><p>According to the storage model we can set up the corresponding database. Two SQL statements are supported for creating databases, as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#C678DD;"> database</span><span style="color:#61AFEF;"> root</span><span style="color:#ABB2BF;">.ln;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#C678DD;"> database</span><span style="color:#61AFEF;"> root</span><span style="color:#ABB2BF;">.sgcc;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>We can thus create two databases using the above two SQL statements.</p><p>It is worth noting that 1 database is recommended.</p><p>When the path itself or the parent/child layer of the path is already created as database, the path is then not allowed to be created as database.</p><p>For example, when the databases root.ln and root.sgcc already exist, creating the database root.ln.wf01 is not allowed. The system will return the corresponding error message as shown below:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#61AFEF;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">Msg: </span><span style="color:#D19A66;">org</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">apache</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">iotdb</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">jdbc</span><span style="color:#ABB2BF;">.IoTDBSQLException: </span><span style="color:#D19A66;">501</span><span style="color:#ABB2BF;">: </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;"> has already been created </span><span style="color:#C678DD;">as</span><span style="color:#ABB2BF;"> a </span><span style="color:#C678DD;">database</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>Similarly, when the database root.db.test already exists, creating the database root.db is not allowed either. The system will return the corresponding error message as shown below:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#61AFEF;"> root</span><span style="color:#ABB2BF;">.db;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">Msg: </span><span style="color:#D19A66;">org</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">apache</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">iotdb</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">jdbc</span><span style="color:#ABB2BF;">.IoTDBSQLException: </span><span style="color:#D19A66;">529</span><span style="color:#ABB2BF;">: Some children of </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db</span><span style="color:#ABB2BF;"> have already been created </span><span style="color:#C678DD;">as</span><span style="color:#ABB2BF;"> datab</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>Database Node Naming Rules:</p><ol><li>Node names may contain: <strong>Chinese/English letters, Digits (0-9), Underscore(_)、Period (.)、Backtick(`)</strong></li><li>The entire name must be enclosed in <strong>backticks (`)</strong> if: <ul><li>It consists solely of digits (e.g., 12345)</li><li>It contains special characters (. or _) that may cause ambiguity (e.g., db.01, _temp)</li></ul></li><li>Escaping Backticks:<br> If the node name itself contains a backtick (`), use <strong>two consecutive backticks(``)</strong> to represent a single backtick. Example: To name a node as `db123`` (containing one backtick), write it as `db123```.</li></ol><p>Besides, if deploy on Windows system, the LayerName is case-insensitive, which means it's not allowed to create databases <code>root.ln</code> and <code>root.LN</code> at the same time.</p><h3 id="_1-2-show-databases" tabindex="-1"><a class="header-anchor" href="#_1-2-show-databases"><span>1.2 Show Databases</span></a></h3><p>After creating the database, we can use the <a href="../SQL-Manual/SQL-Manual_apache">SHOW DATABASES</a> statement and <a href="../SQL-Manual/SQL-Manual_apache">SHOW DATABASES <PathPattern></a> to view the databases. The SQL statements are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW DATABASES;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">SHOW DATABASES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.**;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>The result is as follows:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------+----+-------------------------+-----------------------+-----------------------+</span></span> |
| <span class="line"><span>|database| ttl|schema_replication_factor|data_replication_factor|time_partition_interval|</span></span> |
| <span class="line"><span>+-------------+----+-------------------------+-----------------------+-----------------------+</span></span> |
| <span class="line"><span>| root.sgcc|null| 2| 2| 604800|</span></span> |
| <span class="line"><span>| root.ln|null| 2| 2| 604800|</span></span> |
| <span class="line"><span>+-------------+----+-------------------------+-----------------------+-----------------------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.060s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_1-3-delete-database" tabindex="-1"><a class="header-anchor" href="#_1-3-delete-database"><span>1.3 Delete Database</span></a></h3><p>User can use the <code>DELETE DATABASE <PathPattern></code> statement to delete all databases matching the pathPattern. Please note the data in the database will also be deleted.</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">DELETE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">DELETE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">// </span><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> all </span><span style="color:#C678DD;">data</span><span style="color:#ABB2BF;">, all timeseries </span><span style="color:#C678DD;">and</span><span style="color:#ABB2BF;"> all databases;</span></span> |
| <span class="line"><span style="color:#C678DD;">DELETE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#C678DD;"> root</span><span style="color:#ABB2BF;">.**;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_1-4-count-databases" tabindex="-1"><a class="header-anchor" href="#_1-4-count-databases"><span>1.4 Count Databases</span></a></h3><p>User can use the <code>COUNT DATABASE <PathPattern></code> statement to count the number of databases. It is allowed to specify <code>PathPattern</code> to count the number of databases matching the <code>PathPattern</code>.</p><p>SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">count databases;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count databases </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.*;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count databases </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.*;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count databases </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The result is as follows:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| database|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| root.sgcc|</span></span> |
| <span class="line"><span>| root.turbine|</span></span> |
| <span class="line"><span>| root.ln|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>Total line number = 3</span></span> |
| <span class="line"><span>It costs 0.003s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| database|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| 3|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.003s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| database|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| 3|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| database|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| 0|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| database|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>| 1|</span></span> |
| <span class="line"><span>+-------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_1-5-setting-up-heterogeneous-databases-advanced-operations" tabindex="-1"><a class="header-anchor" href="#_1-5-setting-up-heterogeneous-databases-advanced-operations"><span>1.5 Setting up heterogeneous databases (Advanced operations)</span></a></h3><p>Under the premise of familiar with IoTDB metadata modeling,<br> users can set up heterogeneous databases in IoTDB to cope with different production needs.</p><p>Currently, the following database heterogeneous parameters are supported:</p><table><thead><tr><th>Parameter</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td>TTL</td><td>Long</td><td>TTL of the Database</td></tr><tr><td>SCHEMA_REPLICATION_FACTOR</td><td>Integer</td><td>The schema replication number of the Database</td></tr><tr><td>DATA_REPLICATION_FACTOR</td><td>Integer</td><td>The data replication number of the Database</td></tr><tr><td>SCHEMA_REGION_GROUP_NUM</td><td>Integer</td><td>The SchemaRegionGroup number of the Database</td></tr><tr><td>DATA_REGION_GROUP_NUM</td><td>Integer</td><td>The DataRegionGroup number of the Database</td></tr></tbody></table><p>Note the following when configuring heterogeneous parameters:</p><ul><li>TTL and TIME_PARTITION_INTERVAL must be positive integers.</li><li>SCHEMA_REPLICATION_FACTOR and DATA_REPLICATION_FACTOR must be smaller than or equal to the number of deployed DataNodes.</li><li>The function of SCHEMA_REGION_GROUP_NUM and DATA_REGION_GROUP_NUM are related to the parameter <code>schema_region_group_extension_policy</code> and <code>data_region_group_extension_policy</code> in iotdb-system.properties configuration file. Take DATA_REGION_GROUP_NUM as an example:<br> If <code>data_region_group_extension_policy=CUSTOM</code> is set, DATA_REGION_GROUP_NUM serves as the number of DataRegionGroups owned by the Database.<br> If <code>data_region_group_extension_policy=AUTO</code>, DATA_REGION_GROUP_NUM is used as the lower bound of the DataRegionGroup quota owned by the Database. That is, when the Database starts writing data, it will have at least this number of DataRegionGroups.</li></ul><p>Users can set any heterogeneous parameters when creating a Database, or adjust some heterogeneous parameters during a stand-alone/distributed IoTDB run.</p><h4 id="set-heterogeneous-parameters-when-creating-a-database" tabindex="-1"><a class="header-anchor" href="#set-heterogeneous-parameters-when-creating-a-database"><span>Set heterogeneous parameters when creating a Database</span></a></h4><p>The user can set any of the above heterogeneous parameters when creating a Database. The SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#61AFEF;"> prefixPath</span><span style="color:#ABB2BF;"> (</span><span style="color:#C678DD;">WITH</span><span style="color:#ABB2BF;"> databaseAttributeClause (COMMA? databaseAttributeClause)*)?</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>For example:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#61AFEF;"> root</span><span style="color:#ABB2BF;">.db </span><span style="color:#C678DD;">WITH</span><span style="color:#ABB2BF;"> SCHEMA_REPLICATION_FACTOR</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">, DATA_REPLICATION_FACTOR</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">3</span><span style="color:#ABB2BF;">, SCHEMA_REGION_GROUP_NUM</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">, DATA_REGION_GROUP_NUM</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><h4 id="adjust-heterogeneous-parameters-at-run-time" tabindex="-1"><a class="header-anchor" href="#adjust-heterogeneous-parameters-at-run-time"><span>Adjust heterogeneous parameters at run time</span></a></h4><p>Users can adjust some heterogeneous parameters during the IoTDB runtime, as shown in the following SQL statement:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#ABB2BF;"> prefixPath </span><span style="color:#C678DD;">WITH</span><span style="color:#ABB2BF;"> databaseAttributeClause (COMMA? databaseAttributeClause)*</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>For example:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#C678DD;"> DATABASE</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db</span><span style="color:#C678DD;"> WITH</span><span style="color:#ABB2BF;"> SCHEMA_REGION_GROUP_NUM</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">, DATA_REGION_GROUP_NUM</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Note that only the following heterogeneous parameters can be adjusted at runtime:</p><ul><li>SCHEMA_REGION_GROUP_NUM</li><li>DATA_REGION_GROUP_NUM</li></ul><h4 id="show-heterogeneous-databases" tabindex="-1"><a class="header-anchor" href="#show-heterogeneous-databases"><span>Show heterogeneous databases</span></a></h4><p>The user can query the specific heterogeneous configuration of each Database, and the SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW DATABASES DETAILS prefixPath?</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>For example:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW DATABASES DETAILS</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------+--------+-----------------------+---------------------+---------------------+--------------------+-----------------------+-----------------------+------------------+---------------------+---------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#C678DD;">Database</span><span style="color:#ABB2BF;">| TTL|SchemaReplicationFactor|DataReplicationFactor|TimePartitionInterval|SchemaRegionGroupNum|MinSchemaRegionGroupNum|MaxSchemaRegionGroupNum|DataRegionGroupNum|MinDataRegionGroupNum|MaxDataRegionGroupNum|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------+--------+-----------------------+---------------------+---------------------+--------------------+-----------------------+-----------------------+------------------+---------------------+---------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">3</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">604800000</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db2</span><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">86400000</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">604800000</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db3</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">604800000</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------+--------+-----------------------+---------------------+---------------------+--------------------+-----------------------+-----------------------+------------------+---------------------+---------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">Total </span><span style="color:#C678DD;">line</span><span style="color:#C678DD;"> number</span><span style="color:#56B6C2;"> =</span><span style="color:#D19A66;"> 3</span></span> |
| <span class="line"><span style="color:#ABB2BF;">It costs </span><span style="color:#D19A66;">0</span><span style="color:#ABB2BF;">.058s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The query results in each column are as follows:</p><ul><li>The name of the Database</li><li>The TTL of the Database</li><li>The schema replication number of the Database</li><li>The data replication number of the Database</li><li>The time partition interval of the Database</li><li>The current SchemaRegionGroup number of the Database</li><li>The required minimum SchemaRegionGroup number of the Database</li><li>The permitted maximum SchemaRegionGroup number of the Database</li><li>The current DataRegionGroup number of the Database</li><li>The required minimum DataRegionGroup number of the Database</li><li>The permitted maximum DataRegionGroup number of the Database</li></ul><h3 id="_1-6-ttl" tabindex="-1"><a class="header-anchor" href="#_1-6-ttl"><span>1.6 TTL</span></a></h3><p>IoTDB supports setting data retention time (TTL) at the device level, allowing the system to automatically and periodically delete old data to effectively control disk space and maintain high query performance and low memory usage. TTL is set in milliseconds by default. Once data expires, it cannot be queried or written, but physical deletion is delayed until compaction. Please note that changes to TTL may temporarily affect data queryability, and if TTL is reduced or removed, previously invisible data due to TTL may reappear.</p><p>Important notes:</p><ul><li>TTL is set in milliseconds and is not affected by the time precision in the configuration file.</li><li>Changes to TTL may affect data queryability.</li><li>The system will eventually remove expired data, but there may be a delay.</li><li>TTL determines data expiration based on the data point timestamp, not the ingestion time.</li><li>The system supports setting up to 1000 TTL rules. When the limit is reached, existing rules must be removed before new ones can be added.</li></ul><h4 id="ttl-path-rule" tabindex="-1"><a class="header-anchor" href="#ttl-path-rule"><span>TTL Path Rule</span></a></h4><p>The path can only be prefix paths (i.e., the path cannot contain * , except ** in the last level).<br> This path will match devices and also allows users to specify paths without asterisks as specific databases or devices.<br> When the path does not contain asterisks, the system will check if it matches a database; if it matches a database, both the path and path.** will be set at the same time. Note: Device TTL settings do not verify the existence of metadata, i.e., it is allowed to set TTL for a non-existent device.</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>qualified paths：</span></span> |
| <span class="line"><span>root.**</span></span> |
| <span class="line"><span>root.db.**</span></span> |
| <span class="line"><span>root.db.group1.**</span></span> |
| <span class="line"><span>root.db</span></span> |
| <span class="line"><span>root.db.group1.d1</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>unqualified paths：</span></span> |
| <span class="line"><span>root.*.db</span></span> |
| <span class="line"><span>root.**.db.*</span></span> |
| <span class="line"><span>root.db.*</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h4 id="ttl-applicable-rules" tabindex="-1"><a class="header-anchor" href="#ttl-applicable-rules"><span>TTL Applicable Rules</span></a></h4><p>When a device is subject to multiple TTL rules, the more precise and longer rules are prioritized. For example, for the device "root.bj.hd.dist001.turbine001", the rule "root.bj.hd.dist001.turbine001" takes precedence over "root.bj.hd.dist001.**", and the rule "root.bj.hd.dist001.**" takes precedence over "root.bj.hd.**".</p><h4 id="set-ttl" tabindex="-1"><a class="header-anchor" href="#set-ttl"><span>Set TTL</span></a></h4><p>The set ttl operation can be understood as setting a TTL rule, for example, setting ttl to root.sg.group1.** is equivalent to mounting ttl for all devices that can match this path pattern.<br> The unset ttl operation indicates unmounting TTL for the corresponding path pattern; if there is no corresponding TTL, nothing will be done.<br> If you want to set TTL to be infinitely large, you can use the INF keyword.<br> The SQL Statement for setting TTL is as follow:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">set</span><span style="color:#ABB2BF;"> ttl </span><span style="color:#C678DD;">to</span><span style="color:#ABB2BF;"> pathPattern </span><span style="color:#D19A66;">360000</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Set the Time to Live (TTL) to a pathPattern of 360,000 milliseconds; the pathPattern should not contain a wildcard (*) in the middle and must end with a double asterisk (**). The pathPattern is used to match corresponding devices.<br> To maintain compatibility with older SQL syntax, if the user-provided pathPattern matches a database (db), the path pattern is automatically expanded to include all sub-paths denoted by path.**.<br> For instance, writing "set ttl to <a href="http://root.sg" target="_blank" rel="noopener noreferrer">root.sg</a> 360000" will automatically be transformed into "set ttl to <a href="http://root.sg" target="_blank" rel="noopener noreferrer">root.sg</a>.** 360000", which sets the TTL for all devices under <a href="http://root.sg" target="_blank" rel="noopener noreferrer">root.sg</a>. However, if the specified pathPattern does not match a database, the aforementioned logic will not apply. For example, writing "set ttl to root.sg.group 360000" will not be expanded to "root.sg.group.**" since root.sg.group does not match a database.<br> It is also permissible to specify a particular device without a wildcard (*).</p><h4 id="unset-ttl" tabindex="-1"><a class="header-anchor" href="#unset-ttl"><span>Unset TTL</span></a></h4><p>To unset TTL, we can use follwing SQL statement:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">unset ttl </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>After unset TTL, all data will be accepted in <code>root.ln</code>.</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">unset ttl </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.**</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Unset the TTL in the <code>root.sgcc</code> path.</p><p>New syntax</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">unset ttl </span><span style="color:#C678DD;">from</span><span style="color:#C678DD;"> root</span><span style="color:#ABB2BF;">.**</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Old syntax</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">unset ttl </span><span style="color:#C678DD;">to</span><span style="color:#C678DD;"> root</span><span style="color:#ABB2BF;">.**</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>There is no functional difference between the old and new syntax, and they are compatible with each other.<br> The new syntax is just more conventional in terms of wording.</p><p>Unset the TTL setting for all path pattern.</p><h4 id="show-ttl" tabindex="-1"><a class="header-anchor" href="#show-ttl"><span>Show TTL</span></a></h4><p>To Show TTL, we can use following SQL statement:</p><p>show all ttl</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW ALL TTL</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+--------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">path</span><span style="color:#ABB2BF;">| TTL|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.**|</span><span style="color:#D19A66;">55555555</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg2</span><span style="color:#ABB2BF;">.a.**|</span><span style="color:#D19A66;">44440000</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+--------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>show ttl on pathPattern</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW TTL </span><span style="color:#C678DD;">ON</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db</span><span style="color:#ABB2BF;">.**;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+--------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">path</span><span style="color:#ABB2BF;">| TTL|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db</span><span style="color:#ABB2BF;">.**|</span><span style="color:#D19A66;">55555555</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">db</span><span style="color:#ABB2BF;">.a.**|</span><span style="color:#D19A66;">44440000</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+--------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The SHOW ALL TTL example gives the TTL for all path patterns.<br> The SHOW TTL ON pathPattern shows the TTL for the path pattern specified.</p><p>Display devices' ttl</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show devices</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+---------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| Device|IsAligned| TTL|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+---------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg</span><span style="color:#ABB2BF;">.device1| false| </span><span style="color:#D19A66;">36000000</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg</span><span style="color:#ABB2BF;">.device2| true| INF|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+---------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>All devices will definitely have a TTL, meaning it cannot be null. INF represents infinity.</p><h2 id="_2-device-template" tabindex="-1"><a class="header-anchor" href="#_2-device-template"><span>2. Device Template</span></a></h2><p>IoTDB supports the device template function, enabling different entities of the same type to share metadata, reduce the memory usage of metadata, and simplify the management of numerous entities and measurements.</p><figure><img src="/img/%E6%A8%A1%E6%9D%BF.png" alt="" tabindex="0" loading="lazy"><figcaption></figcaption></figure><figure><img src="/img/templateEN.jpg" alt="" tabindex="0" loading="lazy"><figcaption></figcaption></figure><h3 id="_2-1-create-device-template" tabindex="-1"><a class="header-anchor" href="#_2-1-create-device-template"><span>2.1 Create Device Template</span></a></h3><p>The SQL syntax for creating a metadata template is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#ABB2BF;"> DEVICE TEMPLATE </span><span style="color:#56B6C2;"><</span><span style="color:#ABB2BF;">templateName</span><span style="color:#56B6C2;">></span><span style="color:#ABB2BF;"> ALIGNED? </span><span style="color:#98C379;">'('</span><span style="color:#56B6C2;"> <</span><span style="color:#ABB2BF;">measurementId</span><span style="color:#56B6C2;">></span><span style="color:#56B6C2;"> <</span><span style="color:#ABB2BF;">attributeClauses</span><span style="color:#56B6C2;">></span><span style="color:#E06C75;"> [',' <measurementId> <attributeClauses>]</span><span style="color:#ABB2BF;">+ </span><span style="color:#98C379;">')'</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>Example 1:</strong> Create a template containing two non-aligned timeseries</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> device template t1 (temperature </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">, </span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> BOOLEAN</span><span style="color:#ABB2BF;">)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>Example 2:</strong> Create a template containing a group of aligned timeseries</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> device template t2 aligned (lat </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">, lon </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The<code> lat</code> and <code>lon</code> measurements are aligned.</p><p>When creating a template, the system will automatically assign default encoding and compression methods, requiring no manual specification. If your business scenario requires custom adjustments, you may refer to the following example:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> device template t1 (temperature </span><span style="color:#C678DD;">FLOAT</span><span style="color:#C678DD;"> encoding</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">RLE, </span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> BOOLEAN</span><span style="color:#C678DD;"> encoding</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">PLAIN </span><span style="color:#C678DD;">compression</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">SNAPPY)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>For a full list of supported data types and corresponding encoding methods, please refer to <a class="route-link" href="/UserGuide/latest/Technical-Insider/Encoding-and-Compression.html">Compression & Encoding</a>。</p><h3 id="_2-2-set-device-template" tabindex="-1"><a class="header-anchor" href="#_2-2-set-device-template"><span>2.2 Set Device Template</span></a></h3><p>After a device template is created, it should be set to specific path before creating related timeseries or insert data.</p><p><strong>It should be ensured that the related database has been set before setting template.</strong></p><p><strong>It is recommended to set device template to database path. It is not suggested to set device template to some path above database</strong></p><p><strong>It is forbidden to create timeseries under a path setting s tedeviceplate. Device template shall not be set on a prefix path of an existing timeseries.</strong></p><p>The SQL Statement for setting device template is as follow:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">set</span><span style="color:#ABB2BF;"> device template t1 </span><span style="color:#C678DD;">to</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><h3 id="_2-3-activate-device-template" tabindex="-1"><a class="header-anchor" href="#_2-3-activate-device-template"><span>2.3 Activate Device Template</span></a></h3><p>After setting the device template, with the system enabled to auto create schema, you can insert data into the timeseries. For example, suppose there's a database root.sg1 and t1 has been set to root.sg1.d1, then timeseries like root.sg1.d1.temperature and root.sg1.d1.status are available and data points can be inserted.</p><p><strong>Attention</strong>: Before inserting data or the system not enabled to auto create schema, timeseries defined by the device template will not be created. You can use the following SQL statement to create the timeseries or activate the templdeviceate, act before inserting data:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#C678DD;">using</span><span style="color:#ABB2BF;"> device template </span><span style="color:#C678DD;">on</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>Example:</strong> Execute the following statement</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">set</span><span style="color:#ABB2BF;"> device template t1 </span><span style="color:#C678DD;">to</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1;</span></span> |
| <span class="line"><span style="color:#C678DD;">set</span><span style="color:#ABB2BF;"> device template t2 </span><span style="color:#C678DD;">to</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d2;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#C678DD;">using</span><span style="color:#ABB2BF;"> device template </span><span style="color:#C678DD;">on</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#C678DD;">using</span><span style="color:#ABB2BF;"> device template </span><span style="color:#C678DD;">on</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d2;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Show the time series:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.**</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| timeseries|alias| </span><span style="color:#C678DD;">database</span><span style="color:#ABB2BF;">|dataType|</span><span style="color:#C678DD;">encoding</span><span style="color:#ABB2BF;">|</span><span style="color:#C678DD;">compression</span><span style="color:#ABB2BF;">|tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">temperature</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">| RLE| SNAPPY|</span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">status</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">| PLAIN| SNAPPY|</span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d2</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">lon</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">| GORILLA| SNAPPY|</span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d2</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">lat</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">| GORILLA| SNAPPY|</span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Show the devices:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show devices </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.**</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| devices|isAligned|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1| false|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d2| true|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">---------------+---------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_2-4-show-device-template" tabindex="-1"><a class="header-anchor" href="#_2-4-show-device-template"><span>2.4 Show Device Template</span></a></h3><ul><li>Show all device templates</li></ul><p>The SQL statement looks like this:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show device templates</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The execution result is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|template </span><span style="color:#C678DD;">name</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| t2|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| t1|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li>Show nodes under in device template</li></ul><p>The SQL statement looks like this:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show nodes </span><span style="color:#C678DD;">in</span><span style="color:#ABB2BF;"> device template t1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The execution result is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+--------+--------+-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|child nodes|dataType|</span><span style="color:#C678DD;">encoding</span><span style="color:#ABB2BF;">|</span><span style="color:#C678DD;">compression</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+--------+--------+-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|temperature| </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">| RLE| SNAPPY|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">status</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">| PLAIN| SNAPPY|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+--------+--------+-----------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li>Show the path prefix where a device template is set</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show paths </span><span style="color:#C678DD;">set</span><span style="color:#ABB2BF;"> device template t1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The execution result is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|child paths|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li>Show the path prefix where a device template is used (i.e. the time series has been created)</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show paths </span><span style="color:#C678DD;">using</span><span style="color:#ABB2BF;"> device template t1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The execution result is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|child paths|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">-----------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_2-5-deactivate-device-template" tabindex="-1"><a class="header-anchor" href="#_2-5-deactivate-device-template"><span>2.5 Deactivate device Template</span></a></h3><p>To delete a group of timeseries represented by device template, namely deactivate the device template, use the following SQL statement:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> timeseries of device template t1 </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>or</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">deactivate device template t1 </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The deactivation supports batch process.</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> timeseries of device template t1 </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.*, </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg2</span><span style="color:#ABB2BF;">.*</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>or</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">deactivate device template t1 </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.*, </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg2</span><span style="color:#ABB2BF;">.*</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>If the template name is not provided in sql, all template activation on paths matched by given path pattern will be removed.</p><h3 id="_2-6-unset-device-template" tabindex="-1"><a class="header-anchor" href="#_2-6-unset-device-template"><span>2.6 Unset Device Template</span></a></h3><p>The SQL Statement for unsetting device template is as follow:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">unset device template t1 </span><span style="color:#C678DD;">from</span><span style="color:#D19A66;"> root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>Attention</strong>: It should be guaranteed that none of the timeseries represented by the target device template exists, before unset it. It can be achieved by deactivation operation.</p><h3 id="_2-7-drop-device-template" tabindex="-1"><a class="header-anchor" href="#_2-7-drop-device-template"><span>2.7 Drop Device Template</span></a></h3><p>The SQL Statement for dropping device template is as follow:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">drop</span><span style="color:#ABB2BF;"> device template t1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>Attention</strong>: Dropping an already set template is not supported.</p><h3 id="_2-8-alter-device-template" tabindex="-1"><a class="header-anchor" href="#_2-8-alter-device-template"><span>2.8 Alter Device Template</span></a></h3><p>In a scenario where measurements need to be added, you can modify the template to add measurements to all devicesdevice using the device template.</p><p>The SQL Statement for altering device template is as follow:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">alter</span><span style="color:#ABB2BF;"> device template t1 </span><span style="color:#C678DD;">add</span><span style="color:#ABB2BF;"> (speed </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p><strong>When executing data insertion to devices with device template set on related prefix path and there are measurements not present in this device template, the measurements will be auto added to this device template.</strong></p><h2 id="_3-timeseries-management" tabindex="-1"><a class="header-anchor" href="#_3-timeseries-management"><span>3. Timeseries Management</span></a></h2><h3 id="_3-1-create-timeseries" tabindex="-1"><a class="header-anchor" href="#_3-1-create-timeseries"><span>3.1 Create Timeseries</span></a></h3><p>According to the storage model selected before, we can create corresponding timeseries in the two databases respectively. The SQL statements for creating timeseries are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature </span><span style="color:#C678DD;">with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.hardware </span><span style="color:#C678DD;">with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">TEXT</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf03</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf03</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature </span><span style="color:#C678DD;">with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>From v0.13, you can use a simplified version of the SQL statements to create timeseries:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.hardware </span><span style="color:#C678DD;">TEXT</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf03</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> BOOLEAN</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf03</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>When creating a timeseries, the system will automatically assign default encoding and compression methods, requiring no manual specification. If your business scenario requires custom adjustments, you may refer to the following example:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sgcc</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf03</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature </span><span style="color:#C678DD;">FLOAT</span><span style="color:#C678DD;"> encoding</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">PLAIN compressor</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">SNAPPY</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Note that if you manually specify an encoding method that is incompatible with the data type, the system will return an error message, as shown below:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> WITH</span><span style="color:#ABB2BF;"> DATATYPE</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">BOOLEAN</span><span style="color:#ABB2BF;">, </span><span style="color:#C678DD;">ENCODING</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">TS_2DIFF;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">error: </span><span style="color:#C678DD;">encoding</span><span style="color:#ABB2BF;"> TS_2DIFF does </span><span style="color:#C678DD;">not</span><span style="color:#ABB2BF;"> support </span><span style="color:#C678DD;">BOOLEAN</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>For a full list of supported data types and corresponding encoding methods, please refer to <a class="route-link" href="/UserGuide/latest/Technical-Insider/Encoding-and-Compression.html">Compression & Encoding</a>。</p><h3 id="_3-2-create-aligned-timeseries" tabindex="-1"><a class="header-anchor" href="#_3-2-create-aligned-timeseries"><span>3.2 Create Aligned Timeseries</span></a></h3><p>The SQL statement for creating a group of timeseries are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">CREATE</span><span style="color:#ABB2BF;"> ALIGNED TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">GPS</span><span style="color:#ABB2BF;">(latitude </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">, longitude </span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;">)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>You can set different datatype, encoding, and compression for the timeseries in a group of aligned timeseries</p><p>It is also supported to set an alias, tag, and attribute for aligned timeseries.</p><h3 id="_3-3-delete-timeseries" tabindex="-1"><a class="header-anchor" href="#_3-3-delete-timeseries"><span>3.3 Delete Timeseries</span></a></h3><p>To delete the timeseries we created before, we are able to use <code>(DELETE | DROP) TimeSeries <PathPattern></code> statement.</p><p>The usage are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.temperature, </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.hardware;</span></span> |
| <span class="line"><span style="color:#C678DD;">delete</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.wf02.*;</span></span> |
| <span class="line"><span style="color:#C678DD;">drop</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.wf02.*;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_3-4-show-timeseries" tabindex="-1"><a class="header-anchor" href="#_3-4-show-timeseries"><span>3.4 Show Timeseries</span></a></h3><ul><li><p>SHOW LATEST? TIMESERIES pathPattern? whereClause? limitClause?</p><p>There are four optional clauses added in SHOW TIMESERIES, return information of time series</p></li></ul><p>Timeseries information includes: timeseries path, alias of measurement, database it belongs to, data type, encoding type, compression type, tags and attributes.</p><p>Examples:</p><ul><li><p>SHOW TIMESERIES</p><p>presents all timeseries information in JSON form</p></li><li><p>SHOW TIMESERIES <<code>PathPattern</code>></p><p>returns all timeseries information matching the given <<code>PathPattern</code>>. SQL statements are as follows:</p></li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.**;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.**;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>The results are shown below respectively:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries| alias| database|dataType|encoding|compression| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt01.temperature| null| root.sgcc| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.sgcc.wf03.wt01.status| null| root.sgcc| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.turbine.d1.s1|newAlias| root.turbine| FLOAT| RLE| SNAPPY|{"newTag1":"newV1","tag4":"v4","tag3":"v3"}|{"attr2":"v2","attr1":"newV1","attr4":"v4","attr3":"v3"}| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.hardware| null| root.ln| TEXT| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.temperature| null| root.ln| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 7</span></span> |
| <span class="line"><span>It costs 0.016s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-----------------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries|alias| database|dataType|encoding|compression|tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+-----------------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.hardware| null| root.ln| TEXT| PLAIN| SNAPPY|null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY|null| null| null| null|</span></span> |
| <span class="line"><span>|root.ln.wf01.wt01.temperature| null| root.ln| FLOAT| RLE| SNAPPY|null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY|null| null| null| null|</span></span> |
| <span class="line"><span>+-----------------------------+-----+-------------+--------+--------+-----------+----+----------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 4</span></span> |
| <span class="line"><span>It costs 0.004s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li><p>SHOW TIMESERIES LIMIT INT OFFSET INT</p><p>returns all the timeseries information start from the offset and limit the number of series returned. For example,</p></li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">limit</span><span style="color:#D19A66;"> 10</span><span style="color:#ABB2BF;"> offset </span><span style="color:#D19A66;">10</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li><p>SHOW TIMESERIES WHERE TIMESERIES contains 'containStr'</p><p>The query result set is filtered by string fuzzy matching based on the names of the timeseries. For example:</p></li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> timeseries contains </span><span style="color:#98C379;">'wf01.wt'</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The result is shown below:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries| alias| database|dataType|encoding|compression| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.temperature| null| root.ln| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.016s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li><p>SHOW TIMESERIES WHERE DataType=type</p><p>The query result set is filtered by data type. For example:</p></li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> dataType</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">FLOAT</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The result is shown below:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries| alias| database|dataType|encoding|compression| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt01.temperature| null| root.sgcc| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.turbine.d1.s1|newAlias| root.turbine| FLOAT| RLE| SNAPPY|{"newTag1":"newV1","tag4":"v4","tag3":"v3"}|{"attr2":"v2","attr1":"newV1","attr4":"v4","attr3":"v3"}| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.temperature| null| root.ln| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 3</span></span> |
| <span class="line"><span>It costs 0.016s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li><p>SHOW TIMESERIES WHERE TAGS(KEY) = VALUE</p></li><li><p>SHOW TIMESERIES WHERE TAGS(KEY) CONTAINS VALUE</p><p>The query result set is filtered by tags. For example:</p></li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(unit)</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">'c'</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(</span><span style="color:#C678DD;">description</span><span style="color:#ABB2BF;">) contains </span><span style="color:#98C379;">'test1'</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>The query results are as follows:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries|alias| database|dataType|encoding|compression| tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02.hardware| null| root.ln| TEXT| PLAIN| SNAPPY|{"unit":"c"}| null| null| null|</span></span> |
| <span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.005s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries|alias| database|dataType|encoding|compression| tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY|{"description":"test1"}| null| null| null|</span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.004s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li><p>SHOW LATEST TIMESERIES</p><p>all the returned timeseries information should be sorted in descending order of the last timestamp of timeseries</p></li></ul><p>It is worth noting that when the queried path does not exist, the system will return no timeseries.</p><h3 id="_3-5-count-timeseries" tabindex="-1"><a class="header-anchor" href="#_3-5-count-timeseries"><span>3.5 Count Timeseries</span></a></h3><p>IoTDB is able to use <code>COUNT TIMESERIES <Path></code> to count the number of timeseries matching the path. SQL statements are as follows:</p><ul><li><code>WHERE</code> condition could be used to fuzzy match a time series name with the following syntax: <code>COUNT TIMESERIES <Path> WHERE TIMESERIES contains 'containStr'</code>.</li><li><code>WHERE</code> condition could be used to filter result by data type with the syntax: <code>COUNT TIMESERIES <Path> WHERE DataType=<DataType>'</code>.</li><li><code>WHERE</code> condition could be used to filter result by tags with the syntax: <code>COUNT TIMESERIES <Path> WHERE TAGS(key)='value'</code> or <code>COUNT TIMESERIES <Path> WHERE TAGS(key) contains 'value'</code>.</li><li><code>LEVEL</code> could be defined to show count the number of timeseries of each node at the given level in current Metadata Tree. This could be used to query the number of sensors under each device. The grammar is: <code>COUNT TIMESERIES <Path> GROUP BY LEVEL=<INTEGER></code>.</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.**;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.**;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.*.*.</span><span style="color:#C678DD;">status</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf01</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt01</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">WHERE</span><span style="color:#ABB2BF;"> TIMESERIES contains </span><span style="color:#98C379;">'sgcc'</span><span style="color:#ABB2BF;"> ;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">WHERE</span><span style="color:#ABB2BF;"> DATATYPE </span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;"> INT64;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">WHERE</span><span style="color:#ABB2BF;"> TAGS(unit) contains </span><span style="color:#98C379;">'c'</span><span style="color:#ABB2BF;"> ;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">WHERE</span><span style="color:#ABB2BF;"> TAGS(unit) </span><span style="color:#56B6C2;">=</span><span style="color:#98C379;"> 'c'</span><span style="color:#ABB2BF;"> ;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">WHERE</span><span style="color:#ABB2BF;"> TIMESERIES contains </span><span style="color:#98C379;">'sgcc'</span><span style="color:#C678DD;"> group by</span><span style="color:#C678DD;"> level</span><span style="color:#56B6C2;"> =</span><span style="color:#D19A66;"> 1</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>For example, if there are several timeseries (use <code>show timeseries</code> to show all timeseries):</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries| alias| database|dataType|encoding|compression| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt01.temperature| null| root.sgcc| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.sgcc.wf03.wt01.status| null| root.sgcc| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.turbine.d1.s1|newAlias| root.turbine| FLOAT| RLE| SNAPPY|{"newTag1":"newV1","tag4":"v4","tag3":"v3"}|{"attr2":"v2","attr1":"newV1","attr4":"v4","attr3":"v3"}| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.hardware| null| root.ln| TEXT| PLAIN| SNAPPY| {"unit":"c"}| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY| {"description":"test1"}| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.temperature| null| root.ln| FLOAT| RLE| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY| null| null| null| null|</span></span> |
| <span class="line"><span>+-------------------------------+--------+-------------+--------+--------+-----------+-------------------------------------------+--------------------------------------------------------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 7</span></span> |
| <span class="line"><span>It costs 0.004s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Then the Metadata Tree will be as below:</p><center><img style="width:100%;max-width:600px;margin-left:auto;margin-right:auto;display:block;" src="/img/github/69792176-1718f400-1201-11ea-861a-1a83c07ca144.jpg"></center><p>As can be seen, <code>root</code> is considered as <code>LEVEL=0</code>. So when you enter statements such as:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">GROUP BY</span><span style="color:#C678DD;"> LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">1</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">GROUP BY</span><span style="color:#C678DD;"> LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.wf01.* </span><span style="color:#C678DD;">GROUP BY</span><span style="color:#C678DD;"> LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>You will get following results:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>| column|count(timeseries)|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>| root.sgcc| 2|</span></span> |
| <span class="line"><span>|root.turbine| 1|</span></span> |
| <span class="line"><span>| root.ln| 4|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>Total line number = 3</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>| column|count(timeseries)|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>|root.ln.wf02| 2|</span></span> |
| <span class="line"><span>|root.ln.wf01| 2|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>| column|count(timeseries)|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>|root.ln.wf01| 2|</span></span> |
| <span class="line"><span>+------------+-----------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><blockquote><p>Note: The path of timeseries is just a filter condition, which has no relationship with the definition of level.</p></blockquote><h3 id="_3-6-tag-and-attribute-management" tabindex="-1"><a class="header-anchor" href="#_3-6-tag-and-attribute-management"><span>3.6 Tag and Attribute Management</span></a></h3><p>We can also add an alias, extra tag and attribute information while creating one timeseries.</p><p>The differences between tag and attribute are:</p><ul><li>Tag could be used to query the path of timeseries, we will maintain an inverted index in memory on the tag: Tag -> Timeseries</li><li>Attribute could only be queried by timeseries path : Timeseries -> Attribute</li></ul><p>The SQL statements for creating timeseries with extra tag and attribute information are extended as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#ABB2BF;">(temprature) </span><span style="color:#C678DD;">with</span><span style="color:#ABB2BF;"> datatype</span><span style="color:#56B6C2;">=</span><span style="color:#C678DD;">FLOAT</span><span style="color:#ABB2BF;"> tags(tag1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v1, tag2</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v2) attributes(attr1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v1, attr2</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v2)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The <code>temprature</code> in the brackets is an alias for the sensor <code>s1</code>. So we can use <code>temprature</code> to replace <code>s1</code> anywhere.</p><blockquote><p>IoTDB also supports using AS function to set alias. The difference between the two is: the alias set by the AS function is used to replace the whole time series name, temporary and not bound with the time series; while the alias mentioned above is only used as the alias of the sensor, which is bound with it and can be used equivalent to the original sensor name.</p></blockquote><blockquote><p>Notice that the size of the extra tag and attribute information shouldn't exceed the <code>tag_attribute_total_size</code>.</p></blockquote><p>We can update the tag information after creating it as following:</p><ul><li>Rename the tag/attribute key</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#ABB2BF;"> RENAME tag1 </span><span style="color:#C678DD;">TO</span><span style="color:#ABB2BF;"> newTag1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Reset the tag/attribute value</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#C678DD;"> SET</span><span style="color:#ABB2BF;"> newTag1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">newV1, attr1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">newV1</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Delete the existing tag/attribute</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#C678DD;"> DROP</span><span style="color:#ABB2BF;"> tag1, tag2</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Add new tags</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#C678DD;"> ADD</span><span style="color:#ABB2BF;"> TAGS tag3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, tag4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Add new attributes</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#C678DD;"> ADD</span><span style="color:#ABB2BF;"> ATTRIBUTES attr3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, attr4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Upsert alias, tags and attributes</li></ul><blockquote><p>add alias or a new key-value if the alias or key doesn't exist, otherwise, update the old one with new value.</p></blockquote><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">turbine</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#ABB2BF;"> UPSERT ALIAS</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">newAlias TAGS(tag3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, tag4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4) ATTRIBUTES(attr3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, attr4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4)</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><ul><li>Show timeseries using tags. Use TAGS(tagKey) to identify the tags used as filter key</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW TIMESERIES (</span><span style="color:#56B6C2;"><</span><span style="color:#98C379;">`PathPattern`</span><span style="color:#56B6C2;">></span><span style="color:#ABB2BF;">)? timeseriesWhereClause</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>returns all the timeseries information that satisfy the where condition and match the pathPattern. SQL statements are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.hardware </span><span style="color:#C678DD;">ADD</span><span style="color:#ABB2BF;"> TAGS unit</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">c;</span></span> |
| <span class="line"><span style="color:#C678DD;">ALTER</span><span style="color:#ABB2BF;"> timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wf02</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">wt02</span><span style="color:#ABB2BF;">.</span><span style="color:#C678DD;">status</span><span style="color:#C678DD;"> ADD</span><span style="color:#ABB2BF;"> TAGS </span><span style="color:#C678DD;">description</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">test1;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(unit)</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">'c'</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(</span><span style="color:#C678DD;">description</span><span style="color:#ABB2BF;">) contains </span><span style="color:#98C379;">'test1'</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The results are shown below respectly:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries|alias| database|dataType|encoding|compression| tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02.hardware| null| root.ln| TEXT| PLAIN| SNAPPY|{"unit":"c"}| null| null| null|</span></span> |
| <span class="line"><span>+--------------------------+-----+-------------+--------+--------+-----------+------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.005s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>| timeseries|alias| database|dataType|encoding|compression| tags|attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02.status| null| root.ln| BOOLEAN| PLAIN| SNAPPY|{"description":"test1"}| null| null| null|</span></span> |
| <span class="line"><span>+------------------------+-----+-------------+--------+--------+-----------+-----------------------+----------+--------+-------------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.004s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li>count timeseries using tags</li></ul><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES (</span><span style="color:#56B6C2;"><</span><span style="color:#98C379;">`PathPattern`</span><span style="color:#56B6C2;">></span><span style="color:#ABB2BF;">)? timeseriesWhereClause;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT TIMESERIES (</span><span style="color:#56B6C2;"><</span><span style="color:#98C379;">`PathPattern`</span><span style="color:#56B6C2;">></span><span style="color:#ABB2BF;">)? timeseriesWhereClause </span><span style="color:#C678DD;">GROUP BY</span><span style="color:#C678DD;"> LEVEL</span><span style="color:#56B6C2;">=<</span><span style="color:#C678DD;">INTEGER</span><span style="color:#56B6C2;">></span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>returns all the number of timeseries that satisfy the where condition and match the pathPattern. SQL statements are as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">count timeseries;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count timeseries </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(unit)</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">'c'</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count timeseries </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(unit)</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">'c'</span><span style="color:#C678DD;"> group by</span><span style="color:#C678DD;"> level</span><span style="color:#56B6C2;"> =</span><span style="color:#D19A66;"> 2</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The results are shown below respectly :</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>count timeseries</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>|count(timeseries)|</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>| 6|</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.019s</span></span> |
| <span class="line"><span>count timeseries root.** where TAGS(unit)='c'</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>|count(timeseries)|</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>| 2|</span></span> |
| <span class="line"><span>+-----------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.020s</span></span> |
| <span class="line"><span>count timeseries root.** where TAGS(unit)='c' group by level = 2</span></span> |
| <span class="line"><span>+--------------+-----------------+</span></span> |
| <span class="line"><span>| column|count(timeseries)|</span></span> |
| <span class="line"><span>+--------------+-----------------+</span></span> |
| <span class="line"><span>| root.ln.wf02| 2|</span></span> |
| <span class="line"><span>| root.ln.wf01| 0|</span></span> |
| <span class="line"><span>|root.sgcc.wf03| 0|</span></span> |
| <span class="line"><span>+--------------+-----------------+</span></span> |
| <span class="line"><span>Total line number = 3</span></span> |
| <span class="line"><span>It costs 0.011s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><blockquote><p>Notice that, we only support one condition in the where clause. Either it's an equal filter or it is an <code>contains</code> filter. In both case, the property in the where condition must be a tag.</p></blockquote><p>create aligned timeseries</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">create</span><span style="color:#ABB2BF;"> aligned timeseries </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.d1(s1 INT32 tags(tag1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v1, tag2</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v2) attributes(attr1</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v1, attr2</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v2), s2 DOUBLE tags(tag3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, tag4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4) attributes(attr3</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v3, attr4</span><span style="color:#56B6C2;">=</span><span style="color:#ABB2BF;">v4))</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>The execution result is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| timeseries|alias| </span><span style="color:#C678DD;">database</span><span style="color:#ABB2BF;">|dataType|</span><span style="color:#C678DD;">encoding</span><span style="color:#ABB2BF;">|</span><span style="color:#C678DD;">compression</span><span style="color:#ABB2BF;">| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| INT32| RLE| SNAPPY|{</span><span style="color:#98C379;">"tag1"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v1"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"tag2"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v2"</span><span style="color:#ABB2BF;">}|{</span><span style="color:#98C379;">"attr2"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v2"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"attr1"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v1"</span><span style="color:#ABB2BF;">}| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s2</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| DOUBLE| GORILLA| SNAPPY|{</span><span style="color:#98C379;">"tag4"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v4"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"tag3"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v3"</span><span style="color:#ABB2BF;">}|{</span><span style="color:#98C379;">"attr4"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v4"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"attr3"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v3"</span><span style="color:#ABB2BF;">}| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Support query：</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show timeseries </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> TAGS(tag1)</span><span style="color:#56B6C2;">=</span><span style="color:#98C379;">'v1'</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">| timeseries|alias| </span><span style="color:#C678DD;">database</span><span style="color:#ABB2BF;">|dataType|</span><span style="color:#C678DD;">encoding</span><span style="color:#ABB2BF;">|</span><span style="color:#C678DD;">compression</span><span style="color:#ABB2BF;">| tags| attributes|deadband|deadband parameters|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span> |
| <span class="line"><span style="color:#ABB2BF;">|</span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">d1</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">s1</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">sg1</span><span style="color:#ABB2BF;">| INT32| RLE| SNAPPY|{</span><span style="color:#98C379;">"tag1"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v1"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"tag2"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v2"</span><span style="color:#ABB2BF;">}|{</span><span style="color:#98C379;">"attr2"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v2"</span><span style="color:#ABB2BF;">,</span><span style="color:#98C379;">"attr1"</span><span style="color:#ABB2BF;">:</span><span style="color:#98C379;">"v1"</span><span style="color:#ABB2BF;">}| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">| </span><span style="color:#C678DD;">null</span><span style="color:#ABB2BF;">|</span></span> |
| <span class="line"><span style="color:#ABB2BF;">+</span><span style="color:#7F848E;font-style:italic;">--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The above operations are supported for timeseries tag, attribute updates, etc.</p><h2 id="_4-path-query" tabindex="-1"><a class="header-anchor" href="#_4-path-query"><span>4. Path query</span></a></h2><h3 id="_4-1-path" tabindex="-1"><a class="header-anchor" href="#_4-1-path"><span>4.1 Path</span></a></h3><p>A <code>path</code> is an expression that conforms to the following constraints:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#C678DD;">path</span><span style="color:#ABB2BF;"> </span></span> |
| <span class="line"><span style="color:#ABB2BF;"> : nodeName (</span><span style="color:#98C379;">'.'</span><span style="color:#ABB2BF;"> nodeName)*</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> ;</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> </span></span> |
| <span class="line"><span style="color:#ABB2BF;">nodeName</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> : wildcard? identifier wildcard?</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> | wildcard</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> ;</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> </span></span> |
| <span class="line"><span style="color:#ABB2BF;">wildcard </span></span> |
| <span class="line"><span style="color:#ABB2BF;"> : </span><span style="color:#98C379;">'*'</span><span style="color:#ABB2BF;"> </span></span> |
| <span class="line"><span style="color:#ABB2BF;"> | </span><span style="color:#98C379;">'**'</span></span> |
| <span class="line"><span style="color:#ABB2BF;"> ;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_4-2-nodename" tabindex="-1"><a class="header-anchor" href="#_4-2-nodename"><span>4.2 NodeName</span></a></h3><ul><li>The parts of a path separated by <code>.</code> are called node names (<code>nodeName</code>).</li><li>For example, <code>root.a.b.c</code> is a path with a depth of 4 levels, where <code>root</code>, <code>a</code>, <code>b</code>, and <code>c</code> are all node names.</li></ul><h4 id="constraints" tabindex="-1"><a class="header-anchor" href="#constraints"><span>Constraints</span></a></h4><ul><li><strong>Reserved keyword <code>root</code></strong>: <code>root</code> is a reserved keyword that is only allowed at the beginning of a path. If <code>root</code> appears in any other level, the system will fail to parse it and report an error.</li><li><strong>Character support</strong>: Except for the first level (<code>root</code>), other levels support the following characters: <ul><li>Letters (<code>a-z</code>, <code>A-Z</code>)</li><li>Digits (<code>0-9</code>)</li><li>Underscores (<code>_</code>)</li><li>UNICODE Chinese characters (<code>\u2E80</code> to <code>\u9FFF</code>)</li></ul></li><li><strong>Case sensitivity</strong>: On Windows systems, path node names in the database are case-insensitive. For example, <code>root.ln</code> and <code>root.LN</code> are considered the same path.</li></ul><h3 id="_4-3-special-characters-backquote" tabindex="-1"><a class="header-anchor" href="#_4-3-special-characters-backquote"><span>4.3 Special Characters (Backquote)</span></a></h3><p>If special characters (such as spaces or punctuation marks) are needed in a <code>nodeName</code>, you can enclose the node name in Backquote (`). For more information on the use of backticks, please refer to <a class="route-link" href="/UserGuide/latest/SQL-Manual/Syntax-Rule.html#reverse-quotation-marks">Backquote</a>.</p><h3 id="_4-4-path-pattern" tabindex="-1"><a class="header-anchor" href="#_4-4-path-pattern"><span>4.4 Path Pattern</span></a></h3><p>To make it more convenient and efficient to express multiple time series, IoTDB provides paths with wildcards <code>*</code> and <code>**</code>. Wildcards can appear in any level of a path.</p><ul><li><strong>Single-level wildcard (<code>\*</code>)</strong>: Represents one level in a path. <ul><li>For example, <code>root.vehicle.*.sensor1</code> represents paths with a depth of 4 levels, prefixed by <code>root.vehicle</code> and suffixed by <code>sensor1</code>.</li></ul></li><li><strong>Multi-level wildcard (<code>\**</code>)</strong>: Represents one or more levels (<code>*</code>+). <ul><li>For example: <ul><li><code>root.vehicle.device1.**</code> represents all paths with a depth of 4 or more levels, prefixed by <code>root.vehicle.device1</code>.</li><li><code>root.vehicle.**.sensor1</code> represents paths with a depth of 4 or more levels, prefixed by <code>root.vehicle</code> and suffixed by <code>sensor1</code>.</li></ul></li></ul></li></ul><p><strong>Note</strong>: <code>*</code> and <code>**</code> cannot be placed at the beginning of a path.</p><h3 id="_4-5-show-child-paths" tabindex="-1"><a class="header-anchor" href="#_4-5-show-child-paths"><span>4.5 Show Child Paths</span></a></h3><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW CHILD PATHS pathPattern</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Return all child paths and their node types of all the paths matching pathPattern.</p><p>node types: ROOT -> DB INTERNAL -> DATABASE -> INTERNAL -> DEVICE -> TIMESERIES</p><p>Example：</p><ul><li>return the child paths of root.ln：show child paths root.ln</li></ul><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+------------+----------+</span></span> |
| <span class="line"><span>| child paths|node types|</span></span> |
| <span class="line"><span>+------------+----------+</span></span> |
| <span class="line"><span>|root.ln.wf01| INTERNAL|</span></span> |
| <span class="line"><span>|root.ln.wf02| INTERNAL|</span></span> |
| <span class="line"><span>+------------+----------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.002s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><blockquote><p>get all paths in form of root.xx.xx.xx：show child paths root.xx.xx</p></blockquote><h3 id="_4-6-show-child-nodes" tabindex="-1"><a class="header-anchor" href="#_4-6-show-child-nodes"><span>4.6 Show Child Nodes</span></a></h3><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">SHOW CHILD NODES pathPattern</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div></div></div><p>Return all child nodes of the pathPattern.</p><p>Example：</p><ul><li>return the child nodes of root：show child nodes root</li></ul><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| child nodes|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| ln|</span></span> |
| <span class="line"><span>+------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li>return the child nodes of root.ln：show child nodes root.ln</li></ul><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| child nodes|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| wf01|</span></span> |
| <span class="line"><span>| wf02|</span></span> |
| <span class="line"><span>+------------+</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_4-7-count-nodes" tabindex="-1"><a class="header-anchor" href="#_4-7-count-nodes"><span>4.7 Count Nodes</span></a></h3><p>IoTDB is able to use <code>COUNT NODES <PathPattern> LEVEL=<INTEGER></code> to count the number of nodes at<br> the given level in current Metadata Tree considering a given pattern. IoTDB will find paths that<br> match the pattern and counts distinct nodes at the specified level among the matched paths.<br> This could be used to query the number of devices with specified measurements. The usage are as<br> follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">COUNT NODES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT NODES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">2</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT NODES </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.wf01.** </span><span style="color:#C678DD;">LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">3</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">COUNT NODES </span><span style="color:#C678DD;">root</span><span style="color:#ABB2BF;">.**.temperature </span><span style="color:#C678DD;">LEVEL</span><span style="color:#56B6C2;">=</span><span style="color:#D19A66;">3</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>As for the above mentioned example and Metadata tree, you can get following results:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+------------+</span></span> |
| <span class="line"><span>|count(nodes)|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| 4|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.003s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>|count(nodes)|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| 2|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>|count(nodes)|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| 1|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>|count(nodes)|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>| 2|</span></span> |
| <span class="line"><span>+------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.002s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><blockquote><p>Note: The path of timeseries is just a filter condition, which has no relationship with the definition of level.</p></blockquote><h3 id="_4-8-show-devices" tabindex="-1"><a class="header-anchor" href="#_4-8-show-devices"><span>4.8 Show Devices</span></a></h3><ul><li>SHOW DEVICES pathPattern? (WITH DATABASE)? devicesWhereClause? limitClause?</li></ul><p>Similar to <code>Show Timeseries</code>, IoTDB also supports two ways of viewing devices:</p><ul><li><code>SHOW DEVICES</code> statement presents all devices' information, which is equal to <code>SHOW DEVICES root.**</code>.</li><li><code>SHOW DEVICES <PathPattern></code> statement specifies the <code>PathPattern</code> and returns the devices information matching the pathPattern and under the given level.</li><li><code>WHERE</code> condition supports <code>DEVICE contains 'xxx'</code> to do a fuzzy query based on the device name.</li></ul><p>SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show devices;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show devices </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.**;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show devices </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">where</span><span style="color:#ABB2BF;"> device contains </span><span style="color:#98C379;">'t'</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>You can get results below:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>| devices|isAligned|</span></span> |
| <span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01| false|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02| false|</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt01| false|</span></span> |
| <span class="line"><span>| root.turbine.d1| false|</span></span> |
| <span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>Total line number = 4</span></span> |
| <span class="line"><span>It costs 0.002s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-----------------+---------+</span></span> |
| <span class="line"><span>| devices|isAligned|</span></span> |
| <span class="line"><span>+-----------------+---------+</span></span> |
| <span class="line"><span>|root.ln.wf01.wt01| false|</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02| false|</span></span> |
| <span class="line"><span>+-----------------+---------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.001s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><code>isAligned</code> indicates whether the timeseries under the device are aligned.</p><p>To view devices' information with database, we can use <code>SHOW DEVICES WITH DATABASE</code> statement.</p><ul><li><code>SHOW DEVICES WITH DATABASE</code> statement presents all devices' information with their database.</li><li><code>SHOW DEVICES <PathPattern> WITH DATABASE</code> statement specifies the <code>PathPattern</code> and returns the<br> devices' information under the given level with their database information.</li></ul><p>SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show devices </span><span style="color:#C678DD;">with</span><span style="color:#C678DD;"> database</span><span style="color:#ABB2BF;">;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">show devices </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.** </span><span style="color:#C678DD;">with</span><span style="color:#C678DD;"> database</span><span style="color:#ABB2BF;">;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div></div></div><p>You can get results below:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------+-------------+---------+</span></span> |
| <span class="line"><span>| devices| database|isAligned|</span></span> |
| <span class="line"><span>+-------------------+-------------+---------+</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01| root.ln| false|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02| root.ln| false|</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt01| root.sgcc| false|</span></span> |
| <span class="line"><span>| root.turbine.d1| root.turbine| false|</span></span> |
| <span class="line"><span>+-------------------+-------------+---------+</span></span> |
| <span class="line"><span>Total line number = 4</span></span> |
| <span class="line"><span>It costs 0.003s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+-----------------+-------------+---------+</span></span> |
| <span class="line"><span>| devices| database|isAligned|</span></span> |
| <span class="line"><span>+-----------------+-------------+---------+</span></span> |
| <span class="line"><span>|root.ln.wf01.wt01| root.ln| false|</span></span> |
| <span class="line"><span>|root.ln.wf02.wt02| root.ln| false|</span></span> |
| <span class="line"><span>+-----------------+-------------+---------+</span></span> |
| <span class="line"><span>Total line number = 2</span></span> |
| <span class="line"><span>It costs 0.001s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h3 id="_4-9-count-devices" tabindex="-1"><a class="header-anchor" href="#_4-9-count-devices"><span>4.9 Count Devices</span></a></h3><ul><li>COUNT DEVICES /<!----></li></ul><p>The above statement is used to count the number of devices. At the same time, it is allowed to specify <code>PathPattern</code> to count the number of devices matching the <code>PathPattern</code>.</p><p>SQL statement is as follows:</p><div class="language-sql line-numbers-mode" data-highlighter="shiki" data-ext="sql" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-sql"><span class="line"><span style="color:#ABB2BF;">show devices;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count devices;</span></span> |
| <span class="line"><span style="color:#ABB2BF;">count devices </span><span style="color:#D19A66;">root</span><span style="color:#ABB2BF;">.</span><span style="color:#D19A66;">ln</span><span style="color:#ABB2BF;">.**;</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>You can get results below:</p><div class="language- line-numbers-mode" data-highlighter="shiki" data-ext="" style="background-color:#282c34;color:#abb2bf;"><pre class="shiki one-dark-pro vp-code"><code class="language-"><span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>| devices|isAligned|</span></span> |
| <span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>|root.sgcc.wf03.wt03| false|</span></span> |
| <span class="line"><span>| root.turbine.d1| false|</span></span> |
| <span class="line"><span>| root.ln.wf02.wt02| false|</span></span> |
| <span class="line"><span>| root.ln.wf01.wt01| false|</span></span> |
| <span class="line"><span>+-------------------+---------+</span></span> |
| <span class="line"><span>Total line number = 4</span></span> |
| <span class="line"><span>It costs 0.024s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>|count(devices)|</span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>| 4|</span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.004s</span></span> |
| <span class="line"><span></span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>|count(devices)|</span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>| 2|</span></span> |
| <span class="line"><span>+--------------+</span></span> |
| <span class="line"><span>Total line number = 1</span></span> |
| <span class="line"><span>It costs 0.004s</span></span></code></pre><div class="line-numbers" aria-hidden="true" style="counter-reset:line-number 0;"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></div><!----><!----><!----></div><footer class="vp-page-meta"><div class="vp-meta-item edit-link"><a class="auto-link external-link vp-meta-label" href="https://github.com/apache/iotdb-docs/edit/main/src/UserGuide/latest/Basic-Concept/Operate-Metadata_apache.md" aria-label="Found Error? Edit this page on GitHub" rel="noopener noreferrer" target="_blank"><!--[--><svg xmlns="http://www.w3.org/2000/svg" class="icon edit-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="edit icon" name="edit"><path d="M430.818 653.65a60.46 60.46 0 0 1-50.96-93.281l71.69-114.012 7.773-10.365L816.038 80.138A60.46 60.46 0 0 1 859.225 62a60.46 60.46 0 0 1 43.186 18.138l43.186 43.186a60.46 60.46 0 0 1 0 86.373L588.879 565.55l-8.637 8.637-117.466 68.234a60.46 60.46 0 0 1-31.958 11.229z"></path><path d="M728.802 962H252.891A190.883 190.883 0 0 1 62.008 771.98V296.934a190.883 190.883 0 0 1 190.883-192.61h267.754a60.46 60.46 0 0 1 0 120.92H252.891a69.962 69.962 0 0 0-69.098 69.099V771.98a69.962 69.962 0 0 0 69.098 69.098h475.911A69.962 69.962 0 0 0 797.9 771.98V503.363a60.46 60.46 0 1 1 120.922 0V771.98A190.883 190.883 0 0 1 728.802 962z"></path></svg><!--]-->Found Error? Edit this page on GitHub<!----></a></div><div class="vp-meta-item git-info"><div class="update-time"><span class="vp-meta-label">Last Updated: </span><time class="vp-meta-info" datetime="2026-04-15T10:38:33.000Z" data-allow-mismatch>4/15/26, 10:38 AM</time></div><!----></div></footer><nav class="vp-page-nav"><!----><a class="route-link auto-link next" href="/UserGuide/latest/Basic-Concept/Write-Data_apache.html" aria-label="Write Data"><div class="hint">Next<span class="arrow end"></span></div><div class="link">Write Data<!----></div></a></nav><!----><!----><!--]--></main><!--]--><footer class="site-footer"><span id="doc-version" style="display:none;">latest</span><p class="copyright-text">Copyright © 2026 The Apache Software Foundation. |
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