冬瓜仔

摘要： 增加主键 ALTER TABLE Persons ADD CONSTRAINT pk_PersonID PRIMARY KEY (Id_P,LastName) 组合主键撤消主键 ALTER TABLE Persons DROP CONSTRAINT pk_PersonID增加行 INSERT INTO Persons VALUES ('Gates', 'Bill', 'Xuanwumen 10', 'Beijing');删除行 DELETE FROM 表名称 WHERE 列名称 = 值;修改行 UPDATE Person SET 阅读全文