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ALTER FUNCTION(7)	 PostgreSQL 17.5 Documentation	     ALTER FUNCTION(7)

NAME
       ALTER_FUNCTION -	change the definition of a function

SYNOPSIS
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
	   action [ ...	] [ RESTRICT ]
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
	   RENAME TO new_name
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
	   OWNER TO { new_owner	| CURRENT_ROLE | CURRENT_USER |	SESSION_USER }
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
	   SET SCHEMA new_schema
       ALTER FUNCTION name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ]
	   [ NO	] DEPENDS ON EXTENSION extension_name

       where action is one of:

	   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	execution_cost
	   ROWS	result_rows
	   SUPPORT support_function
	   SET configuration_parameter { TO | =	} { value | DEFAULT }
	   SET configuration_parameter FROM CURRENT
	   RESET configuration_parameter
	   RESET ALL

DESCRIPTION
       ALTER FUNCTION changes the definition of	a function.

       You must	own the	function to use	ALTER FUNCTION.	To change a function's
       schema, you must	also have CREATE privilege on the new schema. To alter
       the owner, you must be able to SET ROLE to the new owning role, and
       that role must have CREATE 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.)

PARAMETERS
       name
	   The name (optionally	schema-qualified) of an	existing function. If
	   no argument list is specified, the name must	be unique in its
	   schema.

       argmode
	   The mode of an argument: IN,	OUT, INOUT, or VARIADIC. If omitted,
	   the default is IN. Note that	ALTER FUNCTION does not	actually pay
	   any attention to OUT	arguments, since only the input	arguments are
	   needed to determine the function's identity.	So it is sufficient to
	   list	the IN,	INOUT, and VARIADIC arguments.

       argname
	   The name of an argument. Note that ALTER FUNCTION does not actually
	   pay any attention to	argument names,	since only the argument	data
	   types are needed to determine the function's	identity.

       argtype
	   The data type(s) of the function's arguments	(optionally
	   schema-qualified), if any.

       new_name
	   The new name	of the function.

       new_owner
	   The new owner of the	function. Note that if the function is marked
	   SECURITY DEFINER, it	will subsequently execute as the new owner.

       new_schema
	   The new schema for the function.

       DEPENDS ON EXTENSION extension_name
       NO DEPENDS ON EXTENSION extension_name
	   This	form marks the function	as dependent on	the extension, or no
	   longer dependent on that extension if NO is specified. A function
	   that's marked as dependent on an extension is dropped when the
	   extension is	dropped, even if CASCADE is not	specified. A function
	   can depend upon multiple extensions,	and will be dropped when any
	   one of those	extensions is dropped.

       CALLED ON NULL INPUT
       RETURNS NULL ON NULL INPUT
       STRICT
	   CALLED ON NULL INPUT	changes	the function so	that it	will be
	   invoked when	some or	all of its arguments are null.	RETURNS	NULL
	   ON NULL INPUT or STRICT changes the function	so that	it is not
	   invoked if any of its arguments are null; instead, a	null result is
	   assumed automatically. See CREATE FUNCTION (CREATE_FUNCTION(7)) for
	   more	information.

       IMMUTABLE
       STABLE
       VOLATILE
	   Change the volatility of the	function to the	specified setting. See
	   CREATE FUNCTION (CREATE_FUNCTION(7))	for details.

       [ EXTERNAL ] SECURITY INVOKER
       [ EXTERNAL ] SECURITY DEFINER
	   Change whether the function is a security definer or	not. The key
	   word	EXTERNAL is ignored for	SQL conformance. See CREATE FUNCTION
	   (CREATE_FUNCTION(7))	for more information about this	capability.

       PARALLEL
	   Change whether the function is deemed safe for parallelism. See
	   CREATE FUNCTION (CREATE_FUNCTION(7))	for details.

       LEAKPROOF
	   Change whether the function is considered leakproof or not. See
	   CREATE FUNCTION (CREATE_FUNCTION(7))	for more information about
	   this	capability.

       COST execution_cost
	   Change the estimated	execution cost of the function.	See CREATE
	   FUNCTION (CREATE_FUNCTION(7)) for more information.

       ROWS result_rows
	   Change the estimated	number of rows returned	by a set-returning
	   function. See CREATE	FUNCTION (CREATE_FUNCTION(7)) for more
	   information.

       SUPPORT support_function
	   Set or change the planner support function to use for this
	   function. See Section 36.11 for details. You	must be	superuser to
	   use this option.

	   This	option cannot be used to remove	the support function
	   altogether, since it	must name a new	support	function. Use CREATE
	   OR REPLACE FUNCTION if you need to do that.

       configuration_parameter
       value
	   Add or change the assignment	to be made to a	configuration
	   parameter when the function is called. If value is DEFAULT or,
	   equivalently, RESET is used,	the function-local setting is removed,
	   so that the function	executes with the value	present	in its
	   environment.	Use RESET ALL to clear all function-local settings.
	   SET FROM CURRENT saves the value of the parameter that is current
	   when	ALTER FUNCTION is executed as the value	to be applied when the
	   function is entered.

	   See SET(7) and Chapter 19 for more information about	allowed
	   parameter names and values.

       RESTRICT
	   Ignored for conformance with	the SQL	standard.

EXAMPLES
       To rename the function sqrt for type integer to square_root:

	   ALTER FUNCTION sqrt(integer)	RENAME TO square_root;

       To change the owner of the function sqrt	for type integer to joe:

	   ALTER FUNCTION sqrt(integer)	OWNER TO joe;

       To change the schema of the function sqrt for type integer to maths:

	   ALTER FUNCTION sqrt(integer)	SET SCHEMA maths;

       To mark the function sqrt for type integer as being dependent on	the
       extension mathlib:

	   ALTER FUNCTION sqrt(integer)	DEPENDS	ON EXTENSION mathlib;

       To adjust the search path that is automatically set for a function:

	   ALTER FUNCTION check_password(text) SET search_path = admin,	pg_temp;

       To disable automatic setting of search_path for a function:

	   ALTER FUNCTION check_password(text) RESET search_path;

       The function will now execute with whatever search path is used by its
       caller.

COMPATIBILITY
       This statement is partially compatible with the ALTER FUNCTION
       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	RESTRICT key
       word, which is optional in PostgreSQL.

SEE ALSO
       CREATE FUNCTION (CREATE_FUNCTION(7)), DROP FUNCTION (DROP_FUNCTION(7)),
       ALTER PROCEDURE (ALTER_PROCEDURE(7)), ALTER ROUTINE (ALTER_ROUTINE(7))

PostgreSQL 17.5			     2025		     ALTER FUNCTION(7)

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