" ALTER TABLE DROP CONSTRAINT ; ALTER TABLE DROP CONSTRAINT ; ALTER TABLE ADD CONSTRAINT CHECK ; ALTER TABLE ADD CONSTRAINT CHECK ; COMMIT; ALTER TABLE DROP INDEX ; ALTER TABLE ADD NOT NULL ; ALTER TABLE ALTER COLUMN ; ALTER TABLE ALTER COLUMN NULL; ALTER TABLE ALTER COLUMN DROP DEFAULT; ALTER TABLE ADD DEFAULT FOR ; ALTER TABLE ADD CONSTRAINT PRIMARY KEY ( , ); ALTER TABLE DROP PRIMARY KEY; ALTER VIEW ALTER VIEW AS CREATE TABLE ( NOT NULL DEFAULT , ); ALTER TABLE ADD CONSTRAINT PRIMARY KEY ( , ); UNIQUE CREATE INDEX ON ( );