有沒有辦法可以創建一個約束來檢查SQL Server中兩列的值？

Question

我有這個DDL：

CREATE TABLE [dbo].[AdminTest] (
    [AdminTestId] INT   IDENTITY (1, 1) NOT NULL, 
    [Title]  NVARCHAR (100) NOT NULL, 
    [CreatedBy] INT   NOT NULL, 
    [CreatedDate] DATETIME  NOT NULL, 
    [ModifiedBy] INT   NOT NULL, 
    [ModifiedDate] DATETIME  NOT NULL, 
    [TestLevelId] INT   NOT NULL, 
    [TestStatusId] INT   NOT NULL, 
    [ExamId]  INT   NOT NULL, 
    [Text]   NVARCHAR (MAX) NULL, 
    [Sequence]  INT   DEFAULT ((1)) NOT NULL, 
    [Release]  NVARCHAR (50) DEFAULT ((1)) NOT NULL, 
    [Version]  ROWVERSION  NOT NULL, 
    [Price]  MONEY   DEFAULT ((0)) NOT NULL, 
    [ReleaseDate] DATETIME  NULL, 
    [Code]   VARCHAR (10) DEFAULT (LEFT(newid(), (5))) NOT NULL 
); 

有，我可以要求ReleaseDate有一個值，如果Release列的值是2的方法嗎？

Answer 1

雖然ALTER：

ALTER TABLE AdminTest 

ADD CONSTRAINT DF_Check CHECK (Release=2) ; 

雖然創造

CREATE TABLE ADMIN(
Release int 
    CONSTRAINT DF_Check CHECK (Release=2) 
) 

Answer 2

您也可以在線定義檢查約束爲列約束，這樣的 -

CREATE TABLE [dbo].[AdminTest] (
    [AdminTestId] INT   IDENTITY (1, 1) NOT NULL, 
    [Release]  NVARCHAR (50) DEFAULT ((1)) NOT NULL, 
    [ReleaseDate] DATETIME NULL CONSTRAINT CK_Release CHECK (Release='2') , 
    [Code]   VARCHAR (10) DEFAULT (LEFT(newid(), (5))) NOT NULL 
);   

Answer 3

是：

alter table dbo.AdminTest 
add constraint CK_AdminTest_VerifyReleaseAndDate CHECK (Release = N'2' AND ReleaseDate IS NOT NULL OR Release <> N'2');