Data Definition Language (DDL) commands provide the means to define a database object, modify its structure after it has been created, and remove it when it is no longer needed. In addition, privileges on such a database object may be granted to or revoked from a database user.
The following SQL commands fall in the category of DDL:
ALTER AUTHORIZATION
ALTER TABLE
CREATE AUTHORIZATION
CREATE DOMAIN
CREATE SCHEMA
CREATE TABLE
CREATE VIEW
DROP
GRANT
RENAME DOMAIN
RENAME TABLE
REVOKE