NAME¶

ALTER_FOREIGN_TABLE - change the definition of a foreign table

SYNOPSIS¶

ALTER FOREIGN TABLE [ IF EXISTS ] name


    action [, ... ]
ALTER FOREIGN TABLE [ IF EXISTS ] name


    RENAME [ COLUMN ] column_name TO new_column_name
ALTER FOREIGN TABLE [ IF EXISTS ] name


    RENAME TO new_name
ALTER FOREIGN TABLE [ IF EXISTS ] name


    SET SCHEMA new_schema
where action is one of:


    ADD [ COLUMN ] column_name data_type [ NULL | NOT NULL ]


    DROP [ COLUMN ] [ IF EXISTS ] column_name [ RESTRICT | CASCADE ]


    ALTER [ COLUMN ] column_name [ SET DATA ] TYPE data_type


    ALTER [ COLUMN ] column_name { SET | DROP } NOT NULL


    ALTER [ COLUMN ] column_name SET STATISTICS integer


    ALTER [ COLUMN ] column_name SET ( attribute_option = value [, ... ] )


    ALTER [ COLUMN ] column_name RESET ( attribute_option [, ... ] )


    ALTER [ COLUMN ] column_name OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ])


    OWNER TO new_owner


    OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ])

DESCRIPTION¶

ALTER FOREIGN TABLE changes the definition of an existing foreign table. There are several subforms:

ADD COLUMN

DROP COLUMN [ IF EXISTS ]

IF EXISTS

SET DATA TYPE

SET/DROP NOT NULL

SET STATISTICS

SET ( attribute_option = value [, ... ] ), RESET ( attribute_option [, ... ] )

OWNER

RENAME

SET SCHEMA

OPTIONS ( [ ADD | SET | DROP ] option ['value'] [, ... ] )

All the actions except RENAME and SET SCHEMA can be combined into a list of multiple alterations to apply in parallel. For example, it is possible to add several columns and/or alter the type of several columns in a single command.

You must own the table to use ALTER FOREIGN TABLE. To change the schema of a foreign table, 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 table's schema. (These restrictions enforce that altering the owner doesn't do anything you couldn't do by dropping and recreating the table. However, a superuser can alter ownership of any table anyway.) To add a column or alter a column type, you must also have USAGE privilege on the data type.

PARAMETERS¶

name

column_name

new_column_name

new_name

data_type

CASCADE

RESTRICT

new_owner

new_schema

NOTES¶

The key word COLUMN is noise and can be omitted.

Consistency with the foreign server is not checked when a column is added or removed with ADD COLUMN or DROP COLUMN, a NOT NULL constraint is added, or a column type is changed with SET DATA TYPE. It is the user's responsibility to ensure that the table definition matches the remote side.

Refer to CREATE FOREIGN TABLE (CREATE_FOREIGN_TABLE(7)) for a further description of valid parameters.

EXAMPLES¶

To mark a column as not-null:

ALTER FOREIGN TABLE distributors ALTER COLUMN street SET NOT NULL;

To change options of a foreign table:

ALTER FOREIGN TABLE myschema.distributors OPTIONS (ADD opt1 'value', SET opt2, 'value2', DROP opt3 'value3');

COMPATIBILITY¶

The forms ADD, DROP, and SET DATA TYPE conform with the SQL standard. The other forms are PostgreSQL extensions of the SQL standard. Also, the ability to specify more than one manipulation in a single ALTER FOREIGN TABLE command is an extension.

ALTER FOREIGN TABLE DROP COLUMN can be used to drop the only column of a foreign table, leaving a zero-column table. This is an extension of SQL, which disallows zero-column foreign tables.