" ALTER TABLE DROP CONSTRAINT ; ALTER TABLE DROP CONSTRAINT ; ALTER TABLE ADD CONSTRAINT CHECK ; ALTER TABLE ADD CONSTRAINT CHECK ; DROP VIEW ; ALTER TABLE DROP CONSTRAINT ; ALTER TABLE ADD CONSTRAINT FOREIGN KEY ( , ) REFERENCES ( , ); ALTER TABLE DROP INDEX ; ALTER TABLE DROP COLUMN ; ALTER TABLE ADD DEFAULT NOT NULL ; ALTER TABLE MODIFY ; ALTER TABLE MODIFY NULL; ALTER TABLE MODIFY NOT NULL; ALTER TABLE MODIFY DEFAULT ; COMMENT ON COLUMN . IS ' '; ALTER TABLE ADD CONSTRAINT PRIMARY KEY ( , ); ALTER TABLE DROP PRIMARY KEY; CREATE OR REPLACE VIEW ( , ) AS ; CREATE TABLE ( NOT NULL DEFAULT , ); ALTER TABLE ADD CONSTRAINT PRIMARY KEY ( , ); UNIQUE CREATE INDEX ON ( );