shiyan6

  数据库的完整性控制熟悉利用企业管理器为列创建DEFAULT约束、为列创建CHECK约束、为列创建UNIQUE约束、为列创建不允许为空约束、创建PRIMARY KEY约束、创建FOREIGN KEY约束(Integrity control of the database use Enterprise Manager to create the familiar column DEFAULT constraint, create a CHECK constraint for a column, create a UNIQUE constraint for a column, create a column does not allow null constraint, create a PRIMARY KEY constraint, create FOREIGN KEY constraint)