doc/src/sgml/ref/drop_function.sgml

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   2 $PostgreSQL$
   3 PostgreSQL documentation
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   5
   6 <refentry id="SQL-DROPFUNCTION">
   7  <refmeta>
   8   <refentrytitle id="SQL-DROPFUNCTION-TITLE">DROP FUNCTION</refentrytitle>
   9   <manvolnum>7</manvolnum>
  10   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  11  </refmeta>
  12
  13  <refnamediv>
  14   <refname>DROP FUNCTION</refname>
  15   <refpurpose>remove a function</refpurpose>
  16  </refnamediv>
  17
  18  <indexterm zone="sql-dropfunction">
  19   <primary>DROP FUNCTION</primary>
  20  </indexterm>
  21
  22  <refsynopsisdiv>
  23 <synopsis>
  24 DROP FUNCTION [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] )
  25     [ CASCADE | RESTRICT ]
  26 </synopsis>
  27  </refsynopsisdiv>
  28
  29  <refsect1>
  30   <title>Description</title>
  31
  32   <para>
  33    <command>DROP FUNCTION</command> removes the definition of an existing
  34    function. To execute this command the user must be the
  35    owner of the function. The argument types to the
  36    function must be specified, since several different functions
  37    can exist with the same name and different argument lists.
  38   </para>
  39  </refsect1>
  40
  41  <refsect1>
  42   <title>Parameters</title>
  43
  44   <variablelist>
  45     <varlistentry>
  46     <term><literal>IF EXISTS</literal></term>
  47     <listitem>
  48      <para>
  49       Do not throw an error if the function does not exist. A notice is issued
  50       in this case.
  51      </para>
  52     </listitem>
  53    </varlistentry>
  54
  55   <varlistentry>
  56     <term><replaceable class="parameter">name</replaceable></term>
  57     <listitem>
  58      <para>
  59       The name (optionally schema-qualified) of an existing function.
  60      </para>
  61     </listitem>
  62    </varlistentry>
  63
  64    <varlistentry>
  65     <term><replaceable class="parameter">argmode</replaceable></term>
  66
  67     <listitem>
  68      <para>
  69       The mode of an argument: <literal>IN</>, <literal>OUT</>,
  70       <literal>INOUT</>, or <literal>VARIADIC</>.
  71       If omitted, the default is <literal>IN</>.
  72       Note that <command>DROP FUNCTION</command> does not actually pay
  73       any attention to <literal>OUT</> arguments, since only the input
  74       arguments are needed to determine the function's identity.
  75       So it is sufficient to list the <literal>IN</>, <literal>INOUT</>,
  76       and <literal>VARIADIC</> arguments.
  77      </para>
  78     </listitem>
  79    </varlistentry>
  80
  81    <varlistentry>
  82     <term><replaceable class="parameter">argname</replaceable></term>
  83
  84     <listitem>
  85      <para>
  86       The name of an argument.
  87       Note that <command>DROP FUNCTION</command> does not actually pay
  88       any attention to argument names, since only the argument data
  89       types are needed to determine the function's identity.
  90      </para>
  91     </listitem>
  92    </varlistentry>
  93
  94    <varlistentry>
  95     <term><replaceable class="parameter">argtype</replaceable></term>
  96
  97     <listitem>
  98      <para>
  99       The data type(s) of the function's arguments (optionally
 100       schema-qualified), if any.
 101      </para>
 102     </listitem>
 103    </varlistentry>
 104
 105    <varlistentry>
 106     <term><literal>CASCADE</literal></term>
 107     <listitem>
 108      <para>
 109       Automatically drop objects that depend on the function (such as
 110       operators or triggers).
 111      </para>
 112     </listitem>
 113    </varlistentry>
 114
 115    <varlistentry>
 116     <term><literal>RESTRICT</literal></term>
 117     <listitem>
 118      <para>
 119       Refuse to drop the function if any objects depend on it.  This
 120       is the default.
 121      </para>
 122     </listitem>
 123    </varlistentry>
 124   </variablelist>
 125  </refsect1>
 126
 127  <refsect1 id="SQL-DROPFUNCTION-examples">
 128   <title>Examples</title>
 129
 130   <para>
 131    This command removes the square root function:
 132
 133 <programlisting>
 134 DROP FUNCTION sqrt(integer);
 135 </programlisting>
 136   </para>
 137  </refsect1>
 138
 139  <refsect1 id="SQL-DROPFUNCTION-compatibility">
 140   <title>Compatibility</title>
 141
 142   <para>
 143    A <command>DROP FUNCTION</command> statement is defined in the SQL
 144    standard, but it is not compatible with this command.
 145   </para>
 146  </refsect1>
 147
 148  <refsect1>
 149   <title>See Also</title>
 150
 151   <simplelist type="inline">
 152    <member><xref linkend="sql-createfunction" endterm="sql-createfunction-title"></member>
 153    <member><xref linkend="sql-alterfunction" endterm="sql-alterfunction-title"></member>
 154   </simplelist>
 155  </refsect1>
 156
 157 </refentry>