Name

ALTER FUNCTION — change the definition of a function

Synopsis

ALTER FUNCTION name ( [ type [, ...] ] ) action [, ... ] [ RESTRICT ]
ALTER FUNCTION name ( [ type [, ...] ] ) RENAME TO newname
ALTER FUNCTION name ( [ type [, ...] ] ) OWNER TO newowner

where action is one of:

    CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT
    IMMUTABLE | STABLE | VOLATILE
    [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER

Description

ALTER FUNCTION changes the definition of a function.

Parameters

name

The name (optionally schema-qualified) of an existing function.

type

The data type of an argument of the function.

newname

The new name of the function.

newowner

The new owner of the function. To change the owner of a function, you must be a superuser. Note that if the function is marked SECURITY DEFINER, it will subsequently execute as the new owner.

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 always returns null if any of its arguments are null. See CREATE FUNCTION for more information.

IMMUTABLE

STABLE

VOLATILE

Change the volatility of the function to the specified type. See CREATE FUNCTION for more information about function volatility.

[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.

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;

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, or change the owner or volatility of a function. The standard also requires the RESTRICT key word; it is optional in PostgreSQL.

See Also

CREATE FUNCTION, DROP FUNCTION,