ALTER TABLE TABLENAME DROP PRIMARY_KEY
執(zhí)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(shè)置被設(shè)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,...);