ALTER FUNCTION
Synopsis
ALTER FUNCTIONname ( [ [argmode ] [argname ]argtype [, ...] ] )action [ ... ] [ RESTRICT ]ALTER FUNCTIONname ( [ [argmode ] [argname ]argtype [, ...] ] ) RENAME TOnew_nameALTER FUNCTIONname ( [ [argmode ] [argname ]argtype [, ...] ] ) OWNER TOnew_ownerALTER FUNCTIONname ( [ [argmode ] [argname ]argtype [, ...] ] ) SET SCHEMAnew_schemawhereaction 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 ALLDescription
ALTER FUNCTION changes the definition of a function.
You must own the function to useALTER FUNCTION. To change a function's schema, you must also haveCREATE 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 haveCREATE 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 thatALTER 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 markedSECURITY 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. SeeCREATE FUNCTION for more information.
- IMMUTABLE
STABLE
VOLATILE Change the volatility of the function to the specified setting. SeeCREATE FUNCTION for details.
- [ EXTERNAL] SECURITY INVOKER
[ EXTERNAL] SECURITY DEFINER Change whether the function is a security definer or not. The key wordEXTERNAL is ignored for SQL conformance. SeeCREATE FUNCTION for more information about this capability.
- LEAKPROOF
Change whether the function is considered leakproof or not. SeeCREATE FUNCTION for more information about this capability.
- COSTexecution_cost
Change the estimated execution cost of the function. SeeCREATE FUNCTION for more information.
- ROWSresult_rows
Change the estimated number of rows returned by a set-returning function. SeeCREATE FUNCTION for more information.
- configuration_parameter
value Add or change the assignment to be made to a configuration parameter when the function is called. Ifvalue 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 session's current value of the parameter as the value to be applied when the function is entered.
SeeSET andChapter 18 for more information about allowed parameter names and values.
- RESTRICT
Ignored for conformance with the SQL standard.
Examples
To rename the functionsqrt for typeinteger tosquare_root:
ALTER FUNCTION sqrt(integer) RENAME TO square_root;
To change the owner of the functionsqrt for typeinteger tojoe:
ALTER FUNCTION sqrt(integer) OWNER TO joe;
To change the schema of the functionsqrt for typeinteger tomaths:
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 ofsearch_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 theALTER 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 theRESTRICT key word, which is optional inPostgreSQL.