ALTER FUNCTION

From PostgreSQL wiki

Revision as of 07:55, 14 June 2013 by Gvim (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Contents

名字

ALTER FUNCTION -- 修改一个函数的定义

语法概要
   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
描述

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.)

参数
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 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.
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.
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 and Chapter 18 for more information about allowed parameter names and values.
RESTRICT
Ignored for conformance with the SQL standard.
示例

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.

兼容性

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.

参见

CREATE FUNCTION, DROP FUNCTION

Personal tools