doc/src/sgml/ref/execute.sgml

   1 <!--
   2 doc/src/sgml/ref/execute.sgml
   3 PostgreSQL documentation
   4 -->
   5
   6 <refentry id="sql-execute">
   7  <indexterm zone="sql-execute">
   8   <primary>EXECUTE</primary>
   9  </indexterm>
  10
  11  <indexterm zone="sql-execute">
  12   <primary>prepared statements</primary>
  13   <secondary>executing</secondary>
  14  </indexterm>
  15
  16  <refmeta>
  17   <refentrytitle>EXECUTE</refentrytitle>
  18   <manvolnum>7</manvolnum>
  19   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  20  </refmeta>
  21
  22  <refnamediv>
  23   <refname>EXECUTE</refname>
  24   <refpurpose>execute a prepared statement</refpurpose>
  25  </refnamediv>
  26
  27  <refsynopsisdiv>
  28 <synopsis>
  29 EXECUTE <replaceable class="parameter">name</replaceable> [ ( <replaceable class="parameter">parameter</replaceable> [, ...] ) ]
  30 </synopsis>
  31  </refsynopsisdiv>
  32
  33  <refsect1>
  34   <title>Description</title>
  35
  36   <para>
  37    <command>EXECUTE</command> is used to execute a previously prepared
  38    statement. Since prepared statements only exist for the duration of a
  39    session, the prepared statement must have been created by a
  40    <command>PREPARE</command> statement executed earlier in the
  41    current session.
  42   </para>
  43
  44   <para>
  45    If the <command>PREPARE</command> statement that created the statement
  46    specified some parameters, a compatible set of parameters must be
  47    passed to the <command>EXECUTE</command> statement, or else an
  48    error is raised. Note that (unlike functions) prepared statements are
  49    not overloaded based on the type or number of their parameters; the
  50    name of a prepared statement must be unique within a database session.
  51   </para>
  52
  53   <para>
  54    For more information on the creation and usage of prepared statements,
  55    see <xref linkend="sql-prepare"/>.
  56   </para>
  57  </refsect1>
  58
  59  <refsect1>
  60   <title>Parameters</title>
  61
  62   <variablelist>
  63    <varlistentry>
  64     <term><replaceable class="parameter">name</replaceable></term>
  65     <listitem>
  66      <para>
  67       The name of the prepared statement to execute.
  68      </para>
  69     </listitem>
  70    </varlistentry>
  71
  72    <varlistentry>
  73     <term><replaceable class="parameter">parameter</replaceable></term>
  74     <listitem>
  75      <para>
  76       The actual value of a parameter to the prepared statement.  This
  77       must be an expression yielding a value that is compatible with
  78       the data type of this parameter, as was determined when the
  79       prepared statement was created.
  80      </para>
  81     </listitem>
  82    </varlistentry>
  83   </variablelist>
  84  </refsect1>
  85
  86  <refsect1>
  87   <title>Outputs</title>
  88    <para>
  89    The command tag returned by <command>EXECUTE</command>
  90    is that of the prepared statement, and not <literal>EXECUTE</literal>.
  91   </para>
  92  </refsect1>
  93
  94  <refsect1>
  95   <title>Examples</title>
  96   <para>
  97     Examples are given in <xref linkend="sql-prepare-examples"/>
  98     in the <xref linkend="sql-prepare"/> documentation.
  99    </para>
 100  </refsect1>
 101
 102  <refsect1>
 103   <title>Compatibility</title>
 104
 105   <para>
 106    The SQL standard includes an <command>EXECUTE</command> statement,
 107    but it is only for use in embedded SQL.  This version of the
 108    <command>EXECUTE</command> statement also uses a somewhat different
 109    syntax.
 110   </para>
 111  </refsect1>
 112
 113  <refsect1>
 114   <title>See Also</title>
 115
 116   <simplelist type="inline">
 117    <member><xref linkend="sql-deallocate"/></member>
 118    <member><xref linkend="sql-prepare"/></member>
 119   </simplelist>
 120  </refsect1>
 121 </refentry>