ALTER FUNCTION — change the definition of a function
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_ROLE | CURRENT_USER | SESSION_USER } ALTER FUNCTIONname
[ ( [ [argmode
] [argname
]argtype
[, ...] ] ) ] SET SCHEMAnew_schema
ALTER FUNCTIONname
[ ( [ [argmode
] [argname
]argtype
[, ...] ] ) ] [ NO ] DEPENDS ON EXTENSIONextension_name
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 PARALLEL { UNSAFE | RESTRICTED | SAFE } COSTexecution_cost
ROWSresult_rows
SUPPORTsupport_function
SETconfiguration_parameter
{ TO | = } {value
| DEFAULT } SETconfiguration_parameter
FROM CURRENT RESETconfiguration_parameter
RESET ALL
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 be able to
SET ROLE
to 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.)
name
The name (optionally schema-qualified) of an existing function. If no argument list is specified, the name must be unique in its schema.
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.
DEPENDS ON EXTENSION extension_name
NO DEPENDS ON EXTENSION extension_name
This form marks the function as dependent on the extension, or no longer
dependent on that extension if NO
is specified.
A function that's marked as dependent on an extension is dropped when the
extension is dropped, even if CASCADE
is not specified.
A function can depend upon multiple extensions, and will be dropped when
any one of those extensions is dropped.
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.
PARALLEL
Change whether the function is deemed safe for parallelism. See CREATE FUNCTION for details.
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.
SUPPORT
support_function
Set or change the planner support function to use for this function. See Section 38.11 for details. You must be superuser to use this option.
This option cannot be used to remove the support function altogether,
since it must name a new support function. Use CREATE OR
REPLACE FUNCTION
if you need to do that.
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 value of the parameter that
is current when ALTER FUNCTION
is executed as the value
to be applied when the function is entered.
See SET and Chapter 19 for more information about allowed parameter names and values.
RESTRICT
Ignored for conformance with the SQL standard.
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 mark the function sqrt
for type
integer
as being dependent on the extension
mathlib
:
ALTER FUNCTION sqrt(integer) DEPENDS ON EXTENSION mathlib;
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.
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.