ALTER TABLE TABLENAME DROP PRIMARY_KEY執行上面的SQL可以刪除主鍵；如果不成功可以用ALTER TABLE TABLENAME DROP CONSTRAINTS COLUMN CASCADE; --刪除約束ALTER TABLE TABLENAME DISABLE PRIMARY_COLUMN ; --設置被設置為主鍵的列為無效DROP INDEX INDEX_NAME; --刪除主鍵索引

SELECT * FROM USER_CONSTRAINTS WHERE CONSTRAINT_TYPE='P' AND TABLE_NAME='你要查看的表名' AND OWNER=USER

ALTER TABLE ADD CONSTRAINTS '約束名' PRIMARY KEY (COLUMN,COLUMN,...);