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diff --git a/doc/src/sgml/ref/alter_function.sgml b/doc/src/sgml/ref/alter_function.sgml new file mode 100644 index 0000000..c5d12af --- /dev/null +++ b/doc/src/sgml/ref/alter_function.sgml @@ -0,0 +1,390 @@ +<!-- +doc/src/sgml/ref/alter_function.sgml +PostgreSQL documentation +--> + +<refentry id="sql-alterfunction"> + <indexterm zone="sql-alterfunction"> + <primary>ALTER FUNCTION</primary> + </indexterm> + + <refmeta> + <refentrytitle>ALTER FUNCTION</refentrytitle> + <manvolnum>7</manvolnum> + <refmiscinfo>SQL - Language Statements</refmiscinfo> + </refmeta> + + <refnamediv> + <refname>ALTER FUNCTION</refname> + <refpurpose>change the definition of a function</refpurpose> + </refnamediv> + + <refsynopsisdiv> +<synopsis> +ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ] + <replaceable class="parameter">action</replaceable> [ ... ] [ RESTRICT ] +ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ] + RENAME TO <replaceable>new_name</replaceable> +ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ] + OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_USER | SESSION_USER } +ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ] + SET SCHEMA <replaceable>new_schema</replaceable> +ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) ] + [ NO ] DEPENDS ON EXTENSION <replaceable>extension_name</replaceable> + +<phrase>where <replaceable class="parameter">action</replaceable> is one of:</phrase> + + CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT + IMMUTABLE | STABLE | VOLATILE + [ NOT ] LEAKPROOF + [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER + PARALLEL { UNSAFE | RESTRICTED | SAFE } + COST <replaceable class="parameter">execution_cost</replaceable> + ROWS <replaceable class="parameter">result_rows</replaceable> + SUPPORT <replaceable class="parameter">support_function</replaceable> + SET <replaceable class="parameter">configuration_parameter</replaceable> { TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT } + SET <replaceable class="parameter">configuration_parameter</replaceable> FROM CURRENT + RESET <replaceable class="parameter">configuration_parameter</replaceable> + RESET ALL +</synopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para> + <command>ALTER FUNCTION</command> changes the definition of a + function. + </para> + + <para> + You must own the function to use <command>ALTER FUNCTION</command>. + To change a function's schema, you must also have <literal>CREATE</literal> + privilege on the new schema. + To alter the owner, you must also be a direct or indirect member of the new + owning role, and that role must have <literal>CREATE</literal> privilege on + the function's schema. (These restrictions enforce that altering the owner + doesn't do anything you couldn't do by dropping and recreating the function. + However, a superuser can alter ownership of any function anyway.) + </para> + </refsect1> + + <refsect1> + <title>Parameters</title> + + <variablelist> + <varlistentry> + <term><replaceable class="parameter">name</replaceable></term> + <listitem> + <para> + The name (optionally schema-qualified) of an existing function. If no + argument list is specified, the name must be unique in its schema. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">argmode</replaceable></term> + + <listitem> + <para> + The mode of an argument: <literal>IN</literal>, <literal>OUT</literal>, + <literal>INOUT</literal>, or <literal>VARIADIC</literal>. + If omitted, the default is <literal>IN</literal>. + Note that <command>ALTER FUNCTION</command> does not actually pay + any attention to <literal>OUT</literal> arguments, since only the input + arguments are needed to determine the function's identity. + So it is sufficient to list the <literal>IN</literal>, <literal>INOUT</literal>, + and <literal>VARIADIC</literal> arguments. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">argname</replaceable></term> + + <listitem> + <para> + The name of an argument. + Note that <command>ALTER FUNCTION</command> does not actually pay + any attention to argument names, since only the argument data + types are needed to determine the function's identity. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">argtype</replaceable></term> + + <listitem> + <para> + The data type(s) of the function's arguments (optionally + schema-qualified), if any. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">new_name</replaceable></term> + <listitem> + <para> + The new name of the function. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">new_owner</replaceable></term> + <listitem> + <para> + The new owner of the function. Note that if the function is + marked <literal>SECURITY DEFINER</literal>, it will subsequently + execute as the new owner. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">new_schema</replaceable></term> + <listitem> + <para> + The new schema for the function. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>DEPENDS ON EXTENSION <replaceable class="parameter">extension_name</replaceable></literal></term> + <term><literal>NO DEPENDS ON EXTENSION <replaceable class="parameter">extension_name</replaceable></literal></term> + <listitem> + <para> + This form marks the function as dependent on the extension, or no longer + dependent on that extension if <literal>NO</literal> is specified. + A function that's marked as dependent on an extension is automatically + dropped when the extension is dropped. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>CALLED ON NULL INPUT</literal></term> + <term><literal>RETURNS NULL ON NULL INPUT</literal></term> + <term><literal>STRICT</literal></term> + + <listitem> + <para><literal>CALLED ON NULL INPUT</literal> changes the function so + that it will be invoked when some or all of its arguments are + null. <literal>RETURNS NULL ON NULL INPUT</literal> or + <literal>STRICT</literal> changes the function so that it is not + invoked if any of its arguments are null; instead, a null result + is assumed automatically. See <xref linkend="sql-createfunction"/> + for more information. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>IMMUTABLE</literal></term> + <term><literal>STABLE</literal></term> + <term><literal>VOLATILE</literal></term> + + <listitem> + <para> + Change the volatility of the function to the specified setting. + See <xref linkend="sql-createfunction"/> for details. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal><optional> EXTERNAL </optional> SECURITY INVOKER</literal></term> + <term><literal><optional> EXTERNAL </optional> SECURITY DEFINER</literal></term> + + <listitem> + <para> + Change whether the function is a security definer or not. The + key word <literal>EXTERNAL</literal> is ignored for SQL + conformance. See <xref linkend="sql-createfunction"/> for more information about + this capability. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>PARALLEL</literal></term> + + <listitem> + <para> + Change whether the function is deemed safe for parallelism. + See <xref linkend="sql-createfunction"/> for details. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>LEAKPROOF</literal></term> + <listitem> + <para> + Change whether the function is considered leakproof or not. + See <xref linkend="sql-createfunction"/> for more information about + this capability. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>COST</literal> <replaceable class="parameter">execution_cost</replaceable></term> + + <listitem> + <para> + Change the estimated execution cost of the function. + See <xref linkend="sql-createfunction"/> for more information. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>ROWS</literal> <replaceable class="parameter">result_rows</replaceable></term> + + <listitem> + <para> + Change the estimated number of rows returned by a set-returning + function. See <xref linkend="sql-createfunction"/> for more information. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>SUPPORT</literal> <replaceable class="parameter">support_function</replaceable></term> + + <listitem> + <para> + Set or change the planner support function to use for this function. + See <xref linkend="xfunc-optimization"/> for details. You must be + superuser to use this option. + </para> + + <para> + This option cannot be used to remove the support function altogether, + since it must name a new support function. Use <command>CREATE OR + REPLACE FUNCTION</command> if you need to do that. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable>configuration_parameter</replaceable></term> + <term><replaceable>value</replaceable></term> + <listitem> + <para> + Add or change the assignment to be made to a configuration parameter + when the function is called. If + <replaceable>value</replaceable> is <literal>DEFAULT</literal> + or, equivalently, <literal>RESET</literal> is used, the function-local + setting is removed, so that the function executes with the value + present in its environment. Use <literal>RESET + ALL</literal> to clear all function-local settings. + <literal>SET FROM CURRENT</literal> saves the value of the parameter that + is current when <command>ALTER FUNCTION</command> is executed as the value + to be applied when the function is entered. + </para> + + <para> + See <xref linkend="sql-set"/> and + <xref linkend="runtime-config"/> + for more information about allowed parameter names and values. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><literal>RESTRICT</literal></term> + + <listitem> + <para> + Ignored for conformance with the SQL standard. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Examples</title> + + <para> + To rename the function <literal>sqrt</literal> for type + <type>integer</type> to <literal>square_root</literal>: +<programlisting> +ALTER FUNCTION sqrt(integer) RENAME TO square_root; +</programlisting> + </para> + + <para> + To change the owner of the function <literal>sqrt</literal> for type + <type>integer</type> to <literal>joe</literal>: +<programlisting> +ALTER FUNCTION sqrt(integer) OWNER TO joe; +</programlisting> + </para> + + <para> + To change the schema of the function <literal>sqrt</literal> for type + <type>integer</type> to <literal>maths</literal>: +<programlisting> +ALTER FUNCTION sqrt(integer) SET SCHEMA maths; +</programlisting> + </para> + + <para> + To mark the function <literal>sqrt</literal> for type + <type>integer</type> as being dependent on the extension + <literal>mathlib</literal>: +<programlisting> +ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib; +</programlisting> + </para> + + <para> + To adjust the search path that is automatically set for a function: +<programlisting> +ALTER FUNCTION check_password(text) SET search_path = admin, pg_temp; +</programlisting> + </para> + + <para> + To disable automatic setting of <varname>search_path</varname> for a function: +<programlisting> +ALTER FUNCTION check_password(text) RESET search_path; +</programlisting> + The function will now execute with whatever search path is used by its + caller. + </para> + </refsect1> + + <refsect1> + <title>Compatibility</title> + + <para> + This statement is partially compatible with the <command>ALTER + FUNCTION</command> statement in the SQL standard. The standard allows more + properties of a function to be modified, but does not provide the + ability to rename a function, make a function a security definer, + attach configuration parameter values to a function, + or change the owner, schema, or volatility of a function. The standard also + requires the <literal>RESTRICT</literal> key word, which is optional in + <productname>PostgreSQL</productname>. + </para> + </refsect1> + + <refsect1> + <title>See Also</title> + + <simplelist type="inline"> + <member><xref linkend="sql-createfunction"/></member> + <member><xref linkend="sql-dropfunction"/></member> + <member><xref linkend="sql-alterprocedure"/></member> + <member><xref linkend="sql-alterroutine"/></member> + </simplelist> + </refsect1> +</refentry> |