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.
ALTER FOREIGN TABLE [ IF EXISTS ] tablename OPTIONS ( {[ SET ] option ['value']} [, ... ]);
Set the owner of a foreign table.
ALTER FOREIGN TABLE [ IF EXISTS ] tablename OWNER TO new_owner;
Update the type of a foreign table column.
ALTER FOREIGN TABLE [ IF EXISTS ] table_name MODIFY ( { column_name data_type [, ...] } );
Modify a column of a foreign table.
ALTER FOREIGN TABLE [ IF EXISTS ] tablename action [, ... ];
The action syntax is as follows:
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.
ALTER FOREIGN TABLE region OPTIONS (SET schema_name 'test');
Change the type of the r_name column to text in the region foreign table.
ALTER FOREIGN TABLE region ALTER r_name TYPE TEXT;
Helpful Links¶
DROP FOREIGN TABLE, CREATE FOREIGN TABLE (SQL on other GaussDB(DWS))