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| <div class="section" id="definitions"> |
| <h1>Definitions<a class="headerlink" href="#definitions" title="Permalink to this headline">¶</a></h1> |
| <div class="section" id="conventions"> |
| <span id="id1"></span><h2>Conventions<a class="headerlink" href="#conventions" title="Permalink to this headline">¶</a></h2> |
| <p>To aid in specifying the CQL syntax, we will use the following conventions in this document:</p> |
| <ul class="simple"> |
| <li>Language rules will be given in an informal <a class="reference external" href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form#Variants">BNF variant</a> notation. In particular, we’ll use square brakets |
| (<code class="docutils literal notranslate"><span class="pre">[</span> <span class="pre">item</span> <span class="pre">]</span></code>) for optional items, <code class="docutils literal notranslate"><span class="pre">*</span></code> and <code class="docutils literal notranslate"><span class="pre">+</span></code> for repeated items (where <code class="docutils literal notranslate"><span class="pre">+</span></code> imply at least one).</li> |
| <li>The grammar will also use the following convention for convenience: non-terminal term will be lowercase (and link to |
| their definition) while terminal keywords will be provided “all caps”. Note however that keywords are |
| <a class="reference internal" href="#identifiers"><span class="std std-ref">Identifiers and keywords</span></a> and are thus case insensitive in practice. We will also define some early construction using |
| regexp, which we’ll indicate with <code class="docutils literal notranslate"><span class="pre">re(<some</span> <span class="pre">regular</span> <span class="pre">expression>)</span></code>.</li> |
| <li>The grammar is provided for documentation purposes and leave some minor details out. For instance, the comma on the |
| last column definition in a <code class="docutils literal notranslate"><span class="pre">CREATE</span> <span class="pre">TABLE</span></code> statement is optional but supported if present even though the grammar in |
| this document suggests otherwise. Also, not everything accepted by the grammar is necessarily valid CQL.</li> |
| <li>References to keywords or pieces of CQL code in running text will be shown in a <code class="docutils literal notranslate"><span class="pre">fixed-width</span> <span class="pre">font</span></code>.</li> |
| </ul> |
| </div> |
| <div class="section" id="identifiers"> |
| <span id="identifiers-and-keywords"></span><h2>Identifiers and keywords<a class="headerlink" href="#identifiers" title="Permalink to this headline">¶</a></h2> |
| <p>The CQL language uses <em>identifiers</em> (or <em>names</em>) to identify tables, columns and other objects. An identifier is a token |
| matching the regular expression <code class="docutils literal notranslate"><span class="pre">[a-zA-Z][a-zA-Z0-9_]*</span></code>.</p> |
| <p>A number of such identifiers, like <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> or <code class="docutils literal notranslate"><span class="pre">WITH</span></code>, are <em>keywords</em>. They have a fixed meaning for the language |
| and most are reserved. The list of those keywords can be found in <a class="reference internal" href="appendices.html#appendix-a"><span class="std std-ref">Appendix A: CQL Keywords</span></a>.</p> |
| <p>Identifiers and (unquoted) keywords are case insensitive. Thus <code class="docutils literal notranslate"><span class="pre">SELECT</span></code> is the same than <code class="docutils literal notranslate"><span class="pre">select</span></code> or <code class="docutils literal notranslate"><span class="pre">sElEcT</span></code>, and |
| <code class="docutils literal notranslate"><span class="pre">myId</span></code> is the same than <code class="docutils literal notranslate"><span class="pre">myid</span></code> or <code class="docutils literal notranslate"><span class="pre">MYID</span></code>. A convention often used (in particular by the samples of this |
| documentation) is to use upper case for keywords and lower case for other identifiers.</p> |
| <p>There is a second kind of identifiers called <em>quoted identifiers</em> defined by enclosing an arbitrary sequence of |
| characters (non empty) in double-quotes(<code class="docutils literal notranslate"><span class="pre">"</span></code>). Quoted identifiers are never keywords. Thus <code class="docutils literal notranslate"><span class="pre">"select"</span></code> is not a |
| reserved keyword and can be used to refer to a column (note that using this is particularly advised), while <code class="docutils literal notranslate"><span class="pre">select</span></code> |
| would raise a parsing error. Also, contrarily to unquoted identifiers and keywords, quoted identifiers are case |
| sensitive (<code class="docutils literal notranslate"><span class="pre">"My</span> <span class="pre">Quoted</span> <span class="pre">Id"</span></code> is <em>different</em> from <code class="docutils literal notranslate"><span class="pre">"my</span> <span class="pre">quoted</span> <span class="pre">id"</span></code>). A fully lowercase quoted identifier that matches |
| <code class="docutils literal notranslate"><span class="pre">[a-zA-Z][a-zA-Z0-9_]*</span></code> is however <em>equivalent</em> to the unquoted identifier obtained by removing the double-quote (so |
| <code class="docutils literal notranslate"><span class="pre">"myid"</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">myid</span></code> and to <code class="docutils literal notranslate"><span class="pre">myId</span></code> but different from <code class="docutils literal notranslate"><span class="pre">"myId"</span></code>). Inside a quoted identifier, the |
| double-quote character can be repeated to escape it, so <code class="docutils literal notranslate"><span class="pre">"foo</span> <span class="pre">""</span> <span class="pre">bar"</span></code> is a valid identifier.</p> |
| <div class="admonition note"> |
| <p class="first admonition-title">Note</p> |
| <p class="last"><em>quoted identifiers</em> allows to declare columns with arbitrary names, and those can sometime clash with |
| specific names used by the server. For instance, when using conditional update, the server will respond with a |
| result-set containing a special result named <code class="docutils literal notranslate"><span class="pre">"[applied]"</span></code>. If you’ve declared a column with such a name, this |
| could potentially confuse some tools and should be avoided. In general, unquoted identifiers should be preferred but |
| if you use quoted identifiers, it is strongly advised to avoid any name enclosed by squared brackets (like |
| <code class="docutils literal notranslate"><span class="pre">"[applied]"</span></code>) and any name that looks like a function call (like <code class="docutils literal notranslate"><span class="pre">"f(x)"</span></code>).</p> |
| </div> |
| <p>More formally, we have:</p> |
| <pre> |
| <strong id="grammar-token-identifier">identifier </strong> ::= <a class="reference internal" href="#grammar-token-unquoted-identifier"><code class="xref docutils literal notranslate"><span class="pre">unquoted_identifier</span></code></a> | <a class="reference internal" href="#grammar-token-quoted-identifier"><code class="xref docutils literal notranslate"><span class="pre">quoted_identifier</span></code></a> |
| <strong id="grammar-token-unquoted-identifier">unquoted_identifier</strong> ::= re('[a-zA-Z][a-zA-Z0-9_]*') |
| <strong id="grammar-token-quoted-identifier">quoted_identifier </strong> ::= '"' (any character where " can appear if doubled)+ '"' |
| </pre> |
| </div> |
| <div class="section" id="constants"> |
| <span id="id2"></span><h2>Constants<a class="headerlink" href="#constants" title="Permalink to this headline">¶</a></h2> |
| <p>CQL defines the following kind of <em>constants</em>:</p> |
| <pre> |
| <strong id="grammar-token-constant">constant</strong> ::= <a class="reference internal" href="#grammar-token-string"><code class="xref docutils literal notranslate"><span class="pre">string</span></code></a> | <a class="reference internal" href="#grammar-token-integer"><code class="xref docutils literal notranslate"><span class="pre">integer</span></code></a> | <a class="reference internal" href="#grammar-token-float"><code class="xref docutils literal notranslate"><span class="pre">float</span></code></a> | <a class="reference internal" href="#grammar-token-boolean"><code class="xref docutils literal notranslate"><span class="pre">boolean</span></code></a> | <a class="reference internal" href="#grammar-token-uuid"><code class="xref docutils literal notranslate"><span class="pre">uuid</span></code></a> | <a class="reference internal" href="#grammar-token-blob"><code class="xref docutils literal notranslate"><span class="pre">blob</span></code></a> | NULL |
| <strong id="grammar-token-string">string </strong> ::= '\'' (any character where ' can appear if doubled)+ '\'' |
| '$$' (any character other than '$$') '$$' |
| <strong id="grammar-token-integer">integer </strong> ::= re('-?[0-9]+') |
| <strong id="grammar-token-float">float </strong> ::= re('-?[0-9]+(\.[0-9]*)?([eE][+-]?[0-9+])?') | NAN | INFINITY |
| <strong id="grammar-token-boolean">boolean </strong> ::= TRUE | FALSE |
| <strong id="grammar-token-uuid">uuid </strong> ::= <a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>{8}-<a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>{4}-<a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>{4}-<a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>{4}-<a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>{12} |
| <strong id="grammar-token-hex">hex </strong> ::= re("[0-9a-fA-F]") |
| <strong id="grammar-token-blob">blob </strong> ::= '0' ('x' | 'X') <a class="reference internal" href="#grammar-token-hex"><code class="xref docutils literal notranslate"><span class="pre">hex</span></code></a>+ |
| </pre> |
| <p>In other words:</p> |
| <ul class="simple"> |
| <li>A string constant is an arbitrary sequence of characters enclosed by single-quote(<code class="docutils literal notranslate"><span class="pre">'</span></code>). A single-quote |
| can be included by repeating it, e.g. <code class="docutils literal notranslate"><span class="pre">'It''s</span> <span class="pre">raining</span> <span class="pre">today'</span></code>. Those are not to be confused with quoted |
| <a class="reference internal" href="#identifiers"><span class="std std-ref">Identifiers and keywords</span></a> that use double-quotes. Alternatively, a string can be defined by enclosing the arbitrary sequence |
| of characters by two dollar characters, in which case single-quote can be used without escaping (<code class="docutils literal notranslate"><span class="pre">$$It's</span> <span class="pre">raining</span> |
| <span class="pre">today$$</span></code>). That latter form is often used when defining <a class="reference internal" href="functions.html#udfs"><span class="std std-ref">user-defined functions</span></a> to avoid having to |
| escape single-quote characters in function body (as they are more likely to occur than <code class="docutils literal notranslate"><span class="pre">$$</span></code>).</li> |
| <li>Integer, float and boolean constant are defined as expected. Note however than float allows the special <code class="docutils literal notranslate"><span class="pre">NaN</span></code> and |
| <code class="docutils literal notranslate"><span class="pre">Infinity</span></code> constants.</li> |
| <li>CQL supports <a class="reference external" href="https://en.wikipedia.org/wiki/Universally_unique_identifier">UUID</a> constants.</li> |
| <li>Blobs content are provided in hexadecimal and prefixed by <code class="docutils literal notranslate"><span class="pre">0x</span></code>.</li> |
| <li>The special <code class="docutils literal notranslate"><span class="pre">NULL</span></code> constant denotes the absence of value.</li> |
| </ul> |
| <p>For how these constants are typed, see the <a class="reference internal" href="types.html#data-types"><span class="std std-ref">Data Types</span></a> section.</p> |
| </div> |
| <div class="section" id="terms"> |
| <h2>Terms<a class="headerlink" href="#terms" title="Permalink to this headline">¶</a></h2> |
| <p>CQL has the notion of a <em>term</em>, which denotes the kind of values that CQL support. Terms are defined by:</p> |
| <pre> |
| <strong id="grammar-token-term">term </strong> ::= <a class="reference internal" href="#grammar-token-constant"><code class="xref docutils literal notranslate"><span class="pre">constant</span></code></a> | <a class="reference internal" href="#grammar-token-literal"><code class="xref docutils literal notranslate"><span class="pre">literal</span></code></a> | <a class="reference internal" href="#grammar-token-function-call"><code class="xref docutils literal notranslate"><span class="pre">function_call</span></code></a> | <a class="reference internal" href="#grammar-token-type-hint"><code class="xref docutils literal notranslate"><span class="pre">type_hint</span></code></a> | <a class="reference internal" href="#grammar-token-bind-marker"><code class="xref docutils literal notranslate"><span class="pre">bind_marker</span></code></a> |
| <strong id="grammar-token-literal">literal </strong> ::= <a class="reference internal" href="types.html#grammar-token-collection-literal"><code class="xref docutils literal notranslate"><span class="pre">collection_literal</span></code></a> | <a class="reference internal" href="types.html#grammar-token-udt-literal"><code class="xref docutils literal notranslate"><span class="pre">udt_literal</span></code></a> | <a class="reference internal" href="types.html#grammar-token-tuple-literal"><code class="xref docutils literal notranslate"><span class="pre">tuple_literal</span></code></a> |
| <strong id="grammar-token-function-call">function_call</strong> ::= <a class="reference internal" href="#grammar-token-identifier"><code class="xref docutils literal notranslate"><span class="pre">identifier</span></code></a> '(' [ <a class="reference internal" href="#grammar-token-term"><code class="xref docutils literal notranslate"><span class="pre">term</span></code></a> (',' <a class="reference internal" href="#grammar-token-term"><code class="xref docutils literal notranslate"><span class="pre">term</span></code></a>)* ] ')' |
| <strong id="grammar-token-type-hint">type_hint </strong> ::= '(' <a class="reference internal" href="types.html#grammar-token-cql-type"><code class="xref docutils literal notranslate"><span class="pre">cql_type</span></code></a> `)` term |
| <strong id="grammar-token-bind-marker">bind_marker </strong> ::= '?' | ':' <a class="reference internal" href="#grammar-token-identifier"><code class="xref docutils literal notranslate"><span class="pre">identifier</span></code></a> |
| </pre> |
| <p>A term is thus one of:</p> |
| <ul class="simple"> |
| <li>A <a class="reference internal" href="#constants"><span class="std std-ref">constant</span></a>.</li> |
| <li>A literal for either <a class="reference internal" href="types.html#collections"><span class="std std-ref">a collection</span></a>, <a class="reference internal" href="types.html#udts"><span class="std std-ref">a user-defined type</span></a> or <a class="reference internal" href="types.html#tuples"><span class="std std-ref">a tuple</span></a> |
| (see the linked sections for details).</li> |
| <li>A function call: see <a class="reference internal" href="functions.html#cql-functions"><span class="std std-ref">the section on functions</span></a> for details on which <a class="reference internal" href="functions.html#native-functions"><span class="std std-ref">native function</span></a> exists and how to define your own <a class="reference internal" href="functions.html#udfs"><span class="std std-ref">user-defined ones</span></a>.</li> |
| <li>A <em>type hint</em>: see the <span class="xref std std-ref">related section</span> for details.</li> |
| <li>A bind marker, which denotes a variable to be bound at execution time. See the section on <a class="reference internal" href="#prepared-statements"><span class="std std-ref">Prepared Statements</span></a> |
| for details. A bind marker can be either anonymous (<code class="docutils literal notranslate"><span class="pre">?</span></code>) or named (<code class="docutils literal notranslate"><span class="pre">:some_name</span></code>). The latter form provides a more |
| convenient way to refer to the variable for binding it and should generally be preferred.</li> |
| </ul> |
| </div> |
| <div class="section" id="comments"> |
| <h2>Comments<a class="headerlink" href="#comments" title="Permalink to this headline">¶</a></h2> |
| <p>A comment in CQL is a line beginning by either double dashes (<code class="docutils literal notranslate"><span class="pre">--</span></code>) or double slash (<code class="docutils literal notranslate"><span class="pre">//</span></code>).</p> |
| <p>Multi-line comments are also supported through enclosure within <code class="docutils literal notranslate"><span class="pre">/*</span></code> and <code class="docutils literal notranslate"><span class="pre">*/</span></code> (but nesting is not supported).</p> |
| <div class="highlight-cql notranslate"><div class="highlight"><pre><span></span><span class="c1">-- This is a comment</span> |
| <span class="c1">// This is a comment too</span> |
| <span class="cm">/* This is</span> |
| <span class="cm"> a multi-line comment */</span> |
| </pre></div> |
| </div> |
| </div> |
| <div class="section" id="statements"> |
| <h2>Statements<a class="headerlink" href="#statements" title="Permalink to this headline">¶</a></h2> |
| <p>CQL consists of statements that can be divided in the following categories:</p> |
| <ul class="simple"> |
| <li><a class="reference internal" href="ddl.html#data-definition"><span class="std std-ref">Data Definition</span></a> statements, to define and change how the data is stored (keyspaces and tables).</li> |
| <li><a class="reference internal" href="dml.html#data-manipulation"><span class="std std-ref">Data Manipulation</span></a> statements, for selecting, inserting and deleting data.</li> |
| <li><a class="reference internal" href="indexes.html#secondary-indexes"><span class="std std-ref">Secondary Indexes</span></a> statements.</li> |
| <li><a class="reference internal" href="mvs.html#materialized-views"><span class="std std-ref">Materialized Views</span></a> statements.</li> |
| <li><a class="reference internal" href="security.html#cql-roles"><span class="std std-ref">Database Roles</span></a> statements.</li> |
| <li><a class="reference internal" href="security.html#cql-permissions"><span class="std std-ref">Permissions</span></a> statements.</li> |
| <li><a class="reference internal" href="functions.html#udfs"><span class="std std-ref">User-Defined Functions</span></a> statements.</li> |
| <li><a class="reference internal" href="types.html#udts"><span class="std std-ref">User-Defined Types</span></a> statements.</li> |
| <li><a class="reference internal" href="triggers.html#cql-triggers"><span class="std std-ref">Triggers</span></a> statements.</li> |
| </ul> |
| <p>All the statements are listed below and are described in the rest of this documentation (see links above):</p> |
| <pre> |
| <strong id="grammar-token-cql-statement">cql_statement </strong> ::= <a class="reference internal" href="#grammar-token-statement"><code class="xref docutils literal notranslate"><span class="pre">statement</span></code></a> [ ';' ] |
| <strong id="grammar-token-statement">statement </strong> ::= <a class="reference internal" href="#grammar-token-ddl-statement"><code class="xref docutils literal notranslate"><span class="pre">ddl_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-dml-statement"><code class="xref docutils literal notranslate"><span class="pre">dml_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-secondary-index-statement"><code class="xref docutils literal notranslate"><span class="pre">secondary_index_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-materialized-view-statement"><code class="xref docutils literal notranslate"><span class="pre">materialized_view_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-role-or-permission-statement"><code class="xref docutils literal notranslate"><span class="pre">role_or_permission_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-udf-statement"><code class="xref docutils literal notranslate"><span class="pre">udf_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-udt-statement"><code class="xref docutils literal notranslate"><span class="pre">udt_statement</span></code></a> |
| | <a class="reference internal" href="#grammar-token-trigger-statement"><code class="xref docutils literal notranslate"><span class="pre">trigger_statement</span></code></a> |
| <strong id="grammar-token-ddl-statement">ddl_statement </strong> ::= <a class="reference internal" href="ddl.html#grammar-token-use-statement"><code class="xref docutils literal notranslate"><span class="pre">use_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-create-keyspace-statement"><code class="xref docutils literal notranslate"><span class="pre">create_keyspace_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-alter-keyspace-statement"><code class="xref docutils literal notranslate"><span class="pre">alter_keyspace_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-drop-keyspace-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_keyspace_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-create-table-statement"><code class="xref docutils literal notranslate"><span class="pre">create_table_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-alter-table-statement"><code class="xref docutils literal notranslate"><span class="pre">alter_table_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-drop-table-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_table_statement</span></code></a> |
| | <a class="reference internal" href="ddl.html#grammar-token-truncate-statement"><code class="xref docutils literal notranslate"><span class="pre">truncate_statement</span></code></a> |
| <strong id="grammar-token-dml-statement">dml_statement </strong> ::= <a class="reference internal" href="dml.html#grammar-token-select-statement"><code class="xref docutils literal notranslate"><span class="pre">select_statement</span></code></a> |
| | <a class="reference internal" href="dml.html#grammar-token-insert-statement"><code class="xref docutils literal notranslate"><span class="pre">insert_statement</span></code></a> |
| | <a class="reference internal" href="dml.html#grammar-token-update-statement"><code class="xref docutils literal notranslate"><span class="pre">update_statement</span></code></a> |
| | <a class="reference internal" href="dml.html#grammar-token-delete-statement"><code class="xref docutils literal notranslate"><span class="pre">delete_statement</span></code></a> |
| | <a class="reference internal" href="dml.html#grammar-token-batch-statement"><code class="xref docutils literal notranslate"><span class="pre">batch_statement</span></code></a> |
| <strong id="grammar-token-secondary-index-statement">secondary_index_statement </strong> ::= <a class="reference internal" href="indexes.html#grammar-token-create-index-statement"><code class="xref docutils literal notranslate"><span class="pre">create_index_statement</span></code></a> |
| | <a class="reference internal" href="indexes.html#grammar-token-drop-index-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_index_statement</span></code></a> |
| <strong id="grammar-token-materialized-view-statement">materialized_view_statement </strong> ::= <a class="reference internal" href="mvs.html#grammar-token-create-materialized-view-statement"><code class="xref docutils literal notranslate"><span class="pre">create_materialized_view_statement</span></code></a> |
| | <a class="reference internal" href="mvs.html#grammar-token-drop-materialized-view-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_materialized_view_statement</span></code></a> |
| <strong id="grammar-token-role-or-permission-statement">role_or_permission_statement</strong> ::= <a class="reference internal" href="security.html#grammar-token-create-role-statement"><code class="xref docutils literal notranslate"><span class="pre">create_role_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-alter-role-statement"><code class="xref docutils literal notranslate"><span class="pre">alter_role_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-drop-role-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_role_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-grant-role-statement"><code class="xref docutils literal notranslate"><span class="pre">grant_role_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-revoke-role-statement"><code class="xref docutils literal notranslate"><span class="pre">revoke_role_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-list-roles-statement"><code class="xref docutils literal notranslate"><span class="pre">list_roles_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-grant-permission-statement"><code class="xref docutils literal notranslate"><span class="pre">grant_permission_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-revoke-permission-statement"><code class="xref docutils literal notranslate"><span class="pre">revoke_permission_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-list-permissions-statement"><code class="xref docutils literal notranslate"><span class="pre">list_permissions_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-create-user-statement"><code class="xref docutils literal notranslate"><span class="pre">create_user_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-alter-user-statement"><code class="xref docutils literal notranslate"><span class="pre">alter_user_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-drop-user-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_user_statement</span></code></a> |
| | <a class="reference internal" href="security.html#grammar-token-list-users-statement"><code class="xref docutils literal notranslate"><span class="pre">list_users_statement</span></code></a> |
| <strong id="grammar-token-udf-statement">udf_statement </strong> ::= <a class="reference internal" href="functions.html#grammar-token-create-function-statement"><code class="xref docutils literal notranslate"><span class="pre">create_function_statement</span></code></a> |
| | <a class="reference internal" href="functions.html#grammar-token-drop-function-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_function_statement</span></code></a> |
| | <a class="reference internal" href="functions.html#grammar-token-create-aggregate-statement"><code class="xref docutils literal notranslate"><span class="pre">create_aggregate_statement</span></code></a> |
| | <a class="reference internal" href="functions.html#grammar-token-drop-aggregate-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_aggregate_statement</span></code></a> |
| <strong id="grammar-token-udt-statement">udt_statement </strong> ::= <a class="reference internal" href="types.html#grammar-token-create-type-statement"><code class="xref docutils literal notranslate"><span class="pre">create_type_statement</span></code></a> |
| | <a class="reference internal" href="types.html#grammar-token-alter-type-statement"><code class="xref docutils literal notranslate"><span class="pre">alter_type_statement</span></code></a> |
| | <a class="reference internal" href="types.html#grammar-token-drop-type-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_type_statement</span></code></a> |
| <strong id="grammar-token-trigger-statement">trigger_statement </strong> ::= <a class="reference internal" href="triggers.html#grammar-token-create-trigger-statement"><code class="xref docutils literal notranslate"><span class="pre">create_trigger_statement</span></code></a> |
| | <a class="reference internal" href="triggers.html#grammar-token-drop-trigger-statement"><code class="xref docutils literal notranslate"><span class="pre">drop_trigger_statement</span></code></a> |
| </pre> |
| </div> |
| <div class="section" id="prepared-statements"> |
| <span id="id3"></span><h2>Prepared Statements<a class="headerlink" href="#prepared-statements" title="Permalink to this headline">¶</a></h2> |
| <p>CQL supports <em>prepared statements</em>. Prepared statements are an optimization that allows to parse a query only once but |
| execute it multiple times with different concrete values.</p> |
| <p>Any statement that uses at least one bind marker (see <a class="reference internal" href="#grammar-token-bind-marker"><code class="xref std std-token docutils literal notranslate"><span class="pre">bind_marker</span></code></a>) will need to be <em>prepared</em>. After which the statement |
| can be <em>executed</em> by provided concrete values for each of its marker. The exact details of how a statement is prepared |
| and then executed depends on the CQL driver used and you should refer to your driver documentation.</p> |
| </div> |
| </div> |
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