| import{_ as s,O as n,P as e,ah as a,aW as t}from"./framework-e4340ccd.js";const i={},o=t(`<h1 id="identifier" tabindex="-1"><a class="header-anchor" href="#identifier" aria-hidden="true">#</a> Identifier</h1><h2 id="usage-scenarios" tabindex="-1"><a class="header-anchor" href="#usage-scenarios" aria-hidden="true">#</a> Usage scenarios</h2><p>Certain objects within IoTDB, including <code>TRIGGER</code>, <code>FUNCTION</code>(UDF), <code>CONTINUOUS QUERY</code>, <code>SCHEMA TEMPLATE</code>, <code>USER</code>, <code>ROLE</code>,<code>Pipe</code>,<code>PipeSink</code>,<code>alias</code> and other object names are known as identifiers.</p><h2 id="constraints" tabindex="-1"><a class="header-anchor" href="#constraints" aria-hidden="true">#</a> Constraints</h2><p>Below are basic constraints of identifiers, specific identifiers may have other constraints, for example, <code>user</code> should consists of more than 4 characters.</p><ul><li>Permitted characters in unquoted identifiers: <ul><li>[0-9 a-z A-Z _ ] (letters, digits and underscore)</li><li>['\\u2E80'..'\\u9FFF'] (UNICODE Chinese characters)</li></ul></li><li>Identifiers may begin with a digit, unquoted identifiers can not be a real number.</li><li>Identifiers are case sensitive.</li><li>Key words can be used as an identifier.</li></ul><p><strong>You need to quote the identifier with back quote(\`) in the following cases:</strong></p><ul><li>Identifier contains special characters.</li><li>Identifier that is a real number.</li></ul><h2 id="how-to-use-quotations-marks-in-quoted-identifiers" tabindex="-1"><a class="header-anchor" href="#how-to-use-quotations-marks-in-quoted-identifiers" aria-hidden="true">#</a> How to use quotations marks in quoted identifiers</h2><p><code>'</code> and <code>"</code> can be used directly in quoted identifiers.</p><p>\` may be written as \`\` in quoted identifiers. See the example below:</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create template t1't"t</span> |
| <span class="token keyword">create</span> <span class="token keyword">schema</span> template <span class="token identifier"><span class="token punctuation">\`</span>t1't"t<span class="token punctuation">\`</span></span> |
| <span class="token punctuation">(</span>temperature <span class="token keyword">FLOAT</span> encoding<span class="token operator">=</span>RLE<span class="token punctuation">,</span> <span class="token keyword">status</span> <span class="token keyword">BOOLEAN</span> encoding<span class="token operator">=</span>PLAIN compression<span class="token operator">=</span>SNAPPY<span class="token punctuation">)</span> |
| |
| <span class="token comment"># create template t1\`t</span> |
| <span class="token keyword">create</span> <span class="token keyword">schema</span> template <span class="token identifier"><span class="token punctuation">\`</span>t1\`\`t<span class="token punctuation">\`</span></span> |
| <span class="token punctuation">(</span>temperature <span class="token keyword">FLOAT</span> encoding<span class="token operator">=</span>RLE<span class="token punctuation">,</span> <span class="token keyword">status</span> <span class="token keyword">BOOLEAN</span> encoding<span class="token operator">=</span>PLAIN compression<span class="token operator">=</span>SNAPPY<span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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><h2 id="examples" tabindex="-1"><a class="header-anchor" href="#examples" aria-hidden="true">#</a> Examples</h2><p>Examples of case in which quoted identifier is used ：</p><ul><li><p>Trigger name should be quoted in cases described above ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create trigger named alert.\`listener-sg1d1s1</span> |
| <span class="token keyword">CREATE</span> <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">\`</span>alert.\`\`listener-sg1d1s1<span class="token punctuation">\`</span></span> |
| <span class="token keyword">AFTER</span> <span class="token keyword">INSERT</span> |
| <span class="token keyword">ON</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">.</span>s1 |
| <span class="token keyword">AS</span> <span class="token string">'org.apache.iotdb.db.engine.trigger.example.AlertListener'</span> |
| <span class="token keyword">WITH</span> <span class="token punctuation">(</span> |
| <span class="token string">'lo'</span> <span class="token operator">=</span> <span class="token string">'0'</span><span class="token punctuation">,</span> |
| <span class="token string">'hi'</span> <span class="token operator">=</span> <span class="token string">'100.0'</span> |
| <span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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></li><li><p>UDF name should be quoted in cases described above ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create a funciton named 111, 111 is a real number.</span> |
| <span class="token keyword">CREATE</span> <span class="token keyword">FUNCTION</span> <span class="token identifier"><span class="token punctuation">\`</span>111<span class="token punctuation">\`</span></span> <span class="token keyword">AS</span> <span class="token string">'org.apache.iotdb.udf.UDTFExample'</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>Template name should be quoted in cases described above ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create a template named 111, 111 is a real number.</span> |
| <span class="token keyword">create</span> <span class="token keyword">schema</span> template <span class="token identifier"><span class="token punctuation">\`</span>111<span class="token punctuation">\`</span></span> |
| <span class="token punctuation">(</span>temperature <span class="token keyword">FLOAT</span> encoding<span class="token operator">=</span>RLE<span class="token punctuation">,</span> <span class="token keyword">status</span> <span class="token keyword">BOOLEAN</span> encoding<span class="token operator">=</span>PLAIN compression<span class="token operator">=</span>SNAPPY<span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>User and Role name should be quoted in cases described above, blank space is not allow in User and Role name whether quoted or not ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create user special\`user.</span> |
| <span class="token keyword">CREATE</span> <span class="token keyword">USER</span> <span class="token identifier"><span class="token punctuation">\`</span>special\`\`user.<span class="token punctuation">\`</span></span> <span class="token string">'write_pwd'</span> |
| |
| <span class="token comment"># create role 111</span> |
| <span class="token keyword">CREATE</span> ROLE <span class="token identifier"><span class="token punctuation">\`</span>111<span class="token punctuation">\`</span></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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></li><li><p>Continuous query name should be quoted in cases described above ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create continuous query test.cq</span> |
| <span class="token keyword">CREATE</span> CONTINUOUS QUERY <span class="token identifier"><span class="token punctuation">\`</span>test.cq<span class="token punctuation">\`</span></span> |
| <span class="token keyword">BEGIN</span> |
| <span class="token keyword">SELECT</span> max_value<span class="token punctuation">(</span>temperature<span class="token punctuation">)</span> |
| <span class="token keyword">INTO</span> temperature_max |
| <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span><span class="token operator">*</span><span class="token punctuation">.</span><span class="token operator">*</span> |
| <span class="token keyword">GROUP</span> <span class="token keyword">BY</span> <span class="token keyword">time</span><span class="token punctuation">(</span><span class="token number">10</span>s<span class="token punctuation">)</span> |
| <span class="token keyword">END</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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></li><li><p>Pipe、PipeSink should be quoted in cases described above ：</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token comment"># create PipeSink test.*1</span> |
| <span class="token keyword">CREATE</span> PIPESINK <span class="token identifier"><span class="token punctuation">\`</span>test.*1<span class="token punctuation">\`</span></span> <span class="token keyword">AS</span> IoTDB <span class="token punctuation">(</span><span class="token string">'ip'</span> <span class="token operator">=</span> <span class="token string">'输入你的IP'</span><span class="token punctuation">)</span> |
| |
| <span class="token comment"># create Pipe test.*2</span> |
| <span class="token keyword">CREATE</span> PIPE <span class="token identifier"><span class="token punctuation">\`</span>test.*2<span class="token punctuation">\`</span></span> <span class="token keyword">TO</span> <span class="token identifier"><span class="token punctuation">\`</span>test.*1<span class="token punctuation">\`</span></span> <span class="token keyword">FROM</span> |
| <span class="token punctuation">(</span><span class="token keyword">select</span> <span class="token operator">*</span><span class="token operator">*</span> <span class="token keyword">from</span> root <span class="token keyword">WHERE</span> <span class="token keyword">time</span><span class="token operator">>=</span>yyyy<span class="token operator">-</span>mm<span class="token operator">-</span>dd HH:MM:SS<span class="token punctuation">)</span> <span class="token keyword">WITH</span> <span class="token string">'SyncDelOp'</span> <span class="token operator">=</span> <span class="token string">'true'</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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></li><li><p><code>AS</code> function provided by IoTDB can assign an alias to time series selected in query. Alias can be constant(including string) or identifier.</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token keyword">select</span> s1 <span class="token keyword">as</span> temperature<span class="token punctuation">,</span> s2 <span class="token keyword">as</span> speed <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01<span class="token punctuation">;</span> |
| |
| <span class="token comment"># Header of result dataset</span> |
| <span class="token operator">+</span><span class="token comment">-----------------------------+-----------|-----+</span> |
| <span class="token operator">|</span> <span class="token keyword">Time</span><span class="token operator">|</span>temperature<span class="token operator">|</span>speed<span class="token operator">|</span> |
| <span class="token operator">+</span><span class="token comment">-----------------------------+-----------|-----+</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="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></li><li><p>The key/value of an attribute can be String Literal and identifier, more details can be found at <strong>key-value pair</strong> part.</p></li></ul>`,15);function p(c,l){return n(),e("div",null,[a(` |
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| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
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| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
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| under the License. |
| |
| `),o])}const d=s(i,[["render",p],["__file","Identifier.html.vue"]]);export{d as default}; |
