ALTER FUNCTION
ALTER FUNCTION — change the definition of a function
Synopsis
ALTER FUNCTIONname
( [ [argmode
] [argname
]argtype
[, ...] ] )action
[ ... ] [ RESTRICT ] ALTER FUNCTIONname
( [ [argmode
] [argname
]argtype
[, ...] ] ) RENAME TOnew_name
ALTER FUNCTIONname
( [ [argmode
] [argname
]argtype
[, ...] ] ) OWNER TO {new_owner
| CURRENT_USER | SESSION_USER } ALTER FUNCTIONname
( [ [argmode
] [argname
]argtype
[, ...] ] ) SET SCHEMAnew_schema
whereaction
is one of: CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT IMMUTABLE | STABLE | VOLATILE | [ NOT ] LEAKPROOF [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER COSTexecution_cost
ROWSresult_rows
SETconfiguration_parameter
{ TO | = } {value
| DEFAULT } SETconfiguration_parameter
FROM CURRENT RESETconfiguration_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 also be a direct or indirect member of 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.
argmode
The mode of an argument:
IN
,OUT
,INOUT
, orVARIADIC
. If omitted, the default isIN
. Note thatALTER FUNCTION
does not actually pay any attention toOUT
arguments, since only the input arguments are needed to determine the function's identity. So it is sufficient to list theIN
,INOUT
, andVARIADIC
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.
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
orSTRICT
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 for more information.IMMUTABLE
STABLE
VOLATILE
Change the volatility of the function to the specified setting. See CREATE FUNCTION 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 for more information about this capability.LEAKPROOF
Change whether the function is considered leakproof or not. See CREATE FUNCTION for more information about this capability.
COST
execution_cost
Change the estimated execution cost of the function. See CREATE FUNCTION for more information.
ROWS
result_rows
Change the estimated number of rows returned by a set-returning function. See CREATE FUNCTION for more information.
configuration_parameter
value
Add or change the assignment to be made to a configuration parameter when the function is called. If
value
isDEFAULT
or, equivalently,RESET
is used, the function-local setting is removed, so that the function executes with the value present in its environment. UseRESET ALL
to clear all function-local settings.SET FROM CURRENT
saves the value of the parameter that is current whenALTER FUNCTION
is executed as the value to be applied when the function is entered.See SET and Chapter 18 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 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.