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ALTER FOREIGN TABLE (SQL on other GaussDB(DWS))

Function

Modifies a foreign table in associated analysis.

Precautions

None

Syntax

• Set a foreign table's attributes.

  1 2	ALTER FOREIGN TABLE [ IF EXISTS ] tablename OPTIONS ( {[ SET ] option ['value']} [, ... ]);

• Set the owner of a foreign table.

  1 2	ALTER FOREIGN TABLE [ IF EXISTS ] tablename OWNER TO new_owner;

• Update the type of a foreign table column.

  1 2	ALTER FOREIGN TABLE [ IF EXISTS ] table_name MODIFY ( { column_name data_type [, ...] } );

• Modify a column of a foreign table.

  1 2	ALTER FOREIGN TABLE [ IF EXISTS ] tablename action [, ... ];

  The action syntax is as follows:

  1 2	ALTER [ COLUMN ] column_name [ SET DATA ] TYPE data_type | MODIFY column_name data_type

  For details, see ALTER TABLE.

Parameter Description

• IF EXISTS

  Sends a notification instead of an error if no tables have identical names. The notification prompts that the table you are querying does not exist.

• tablename

  Specifies the name of an existing foreign table to be modified.

  Value range: an existing foreign table name

• new_owner

  Specifies the new owner of the foreign table.

  Value range: a string indicating a valid user name

• data_type

  Specifies the new type for an existing column.

  Value range: a string. It must comply with the naming convention.

• column_name

  Specifies the name of an existing column.

  Value range: a string. It must comply with the naming convention.

For details on how to modify other parameters in the foreign table, see Parameter Description in ALTER TABLE.

Example:

Modify the region option of the foreign table.

1	ALTER FOREIGN TABLE region OPTIONS (SET schema_name 'test');

Change the type of the r_name column to text in the region foreign table.

1	ALTER FOREIGN TABLE region ALTER r_name TYPE TEXT;

Helpful Links

DROP FOREIGN TABLE, CREATE FOREIGN TABLE (SQL on other GaussDB(DWS))

Parent topic: DDL Syntax