![]() Refuse to drop the column or constraint if there are any dependent objects. The role name of the new owner of the external table.Īutomatically drop objects that depend on the dropped column, such as a view that references the column. The name (possibly schema-qualified) of an existing external table definition to alter.ĭata type of the new column, or new data type for an existing column. To modify this information, you must drop and recreate the external table definition. The ALTER EXTERNAL TABLE and ALTER TABLE commands cannot modify the type of the external table (read, write, web), the table FORMAT information, or the location of the external data. A superuser has these privileges automatically.Ĭhanges that you make to an external table definition with either ALTER EXTERNAL TABLE or ALTER TABLE do not affect the external data. 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 external table’s schema. To change the schema of an external table, you must also have CREATE privilege on the new schema. You must own the external table to use ALTER EXTERNAL TABLE or ALTER TABLE. Set (change) the distribution policy (writable external table only).Use the ALTER TABLE command to perform these actions on an external table: OWNER - Changes the owner of the external table to the specified user.ALTER COLUMN TYPE - Changes the data type of a table column.The CASCADE keyword is required if anything outside the table depends on the column, such as a view that references the column. If you drop readable external table columns, it only changes the table definition in Greenplum Database. DROP COLUMN - Drops a column from the external table definition.ADD COLUMN - Adds a new column to the external table definition.These are the supported ALTER EXTERNAL TABLE actions: Synopsis ALTER EXTERNAL TABLE ĪLTER EXTERNAL TABLE changes the definition of an existing external table. Changes the definition of an external table.
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