doc/src/sgml/ref/execute.sgml

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