ALTER FUNCTION(7)                                         SQL Commands                                         ALTER FUNCTION(7)



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 any-
       thing 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 informa-
              tion.

       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  informa-
              tion.

       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  secu-
       rity  definer, attach configuration parameter values to a function, or change the owner, schema, or volatility of a func-
       tion. 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)]



SQL - Language Statements                                  2011-09-22                                          ALTER FUNCTION(7)