1，主键的删除
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ALTER TABLE TABLENAME DROP PRIMARY_KEY执行上面的SQL可以删除主键；如果不成功可以用ALTER TABLE TABLENAME DROP CONSTRAINTS COLUMN CASCADE; --删除约束ALTER TABLE TABLENAME DISABLE PRIMARY_COLUMN ; --设置被设置为主键的列为无效DROP INDEX INDEX_NAME; --删除主键索引 |
2,查看主键约束
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SELECT * FROM USER_CONSTRAINTS WHERE CONSTRAINT_TYPE='P' AND TABLE_NAME='你要查看的表名' AND OWNER=USER |
3,创建联合主键
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ALTER TABLE ADD CONSTRAINTS '约束名' PRIMARY KEY (COLUMN,COLUMN,...); |
