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
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
COST execution_cost
ROWS result_rows
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 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, 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.
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.
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.
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 session’s current value of
the parameter as the value to be applied when the function is
entered.
See SET [set(7)] and in the documentation 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.
SEE ALSO
CREATE FUNCTION [create_function(7)], DROP FUNCTION [drop_function(7)]