ALTER FOREIGN DATA WRAPPER

Changes the definition of a foreign-data wrapper.

Synopsis

ALTER FOREIGN DATA WRAPPER <name>
    [ HANDLER <handler_function> | NO HANDLER ]
    [ VALIDATOR <validator_function> | NO VALIDATOR ]
    [ OPTIONS ( [ ADD | SET | DROP ] <option> ['<value>'] [, ... ] ) ]

ALTER FOREIGN DATA WRAPPER <name> OWNER TO <new_owner>
ALTER FOREIGN DATA WRAPPER <name> RENAME TO <new_name>

Description

ALTER FOREIGN DATA WRAPPER changes the definition of a foreign-data wrapper. The first form of the command changes the support functions or generic options of the foreign-data wrapper. LightDB-A Database requires at least one clause. The second and third forms of the command change the owner or name of the foreign-data wrapper.

Only superusers can alter foreign-data wrappers. Additionally, only superusers can own foreign-data wrappers

Parameters

name : The name of an existing foreign-data wrapper.

HANDLER handler_function : Specifies a new handler function for the foreign-data wrapper.

NO HANDLER : Specifies that the foreign-data wrapper should no longer have a handler function.

> **Note** You cannot access a foreign table that uses a foreign-data wrapper with no handler.

VALIDATOR validator_function : Specifies a new validator function for the foreign-data wrapper.

Options to the foreign-data wrapper, servers, and user mappings may become invalid when you change the validator function. You must make sure that these options are correct before using the modified foreign-data wrapper. Note that LightDB-A Database checks any options specified in this `ALTER FOREIGN DATA WRAPPER` command using the new validator.

NO VALIDATOR : Specifies that the foreign-data wrapper should no longer have a validator function.

OPTIONS ( [ ADD | SET | DROP ] option [‘value’] [, … ] ) : Change the foreign-data wrapper’s options. ADD, SET, and DROP specify the action to perform. If no operation is explicitly specified, the default operation is ADD. Option names must be unique. LightDB-A Database validates names and values using the foreign-data wrapper’s validator function, if any.

OWNER TO new_owner : Specifies the new owner of the foreign-data wrapper. Only superusers can own foreign-data wrappers.

RENAME TO new_name : Specifies the new name of the foreign-data wrapper.

Examples

Change the definition of a foreign-data wrapper named dbi by adding a new option named foo, and removing the option named bar:

ALTER FOREIGN DATA WRAPPER dbi OPTIONS (ADD foo '1', DROP 'bar');

Change the validator function for a foreign-data wrapper named dbi to bob.myvalidator:

ALTER FOREIGN DATA WRAPPER dbi VALIDATOR bob.myvalidator;

Compatibility