ALTER FUNCTION

Changes 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>
ALTER FUNCTION <name> ( [ [<argmode>] [<argname>] <argtype> [, ...] ] )
   SET SCHEMA <new_schema>

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.

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 does not do anything you could not 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: either IN, OUT, or INOUT. 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 and INOUT 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 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 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.

RESTRICT

Ignored for conformance with the SQL standard.

Notes

HAWQ has limitations on the use of functions defined as STABLE or VOLATILE. See CREATE FUNCTION for more information.

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 math:

ALTER FUNCTION sqrt(integer) SET SCHEMA math;

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, schema, or volatility of a function. The standard also requires the RESTRICT key word, which is optional in HAWQ.

See Also

CREATE AGGREGATE, DROP AGGREGATE