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SQL Server中事务transaction如果没写在try catch中,就算中间语句报错还是会提交

时间:2018-10-16 22:10:49      阅读:263      评论:0      收藏:0      [点我收藏+]

标签:primary   报错   ati   tran   off   get   server   插入数据   pdb   

假如我们数据库中有两张表Person和Book

Person表:

CREATE TABLE [dbo].[Person](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [Code] [nvarchar](50) NULL,
    [Name] [nvarchar](50) NULL,
    [CreateTime] [datetime] NULL,
    [UpdateTime] [datetime] NULL,
 CONSTRAINT [PK_Person] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[Person] ADD  CONSTRAINT [DF_Person_CreateTime]  DEFAULT (getdate()) FOR [CreateTime]
GO
CREATE UNIQUE NONCLUSTERED INDEX [IX_Person] ON [dbo].[Person]
(
    [Code] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO

 

Book表:

CREATE TABLE [dbo].[Book](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [BookCode] [nvarchar](50) NULL,
    [BookName] [nvarchar](50) NULL,
    [PersonCode] [nvarchar](50) NULL,
 CONSTRAINT [PK_Book] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[Book]  WITH CHECK ADD  CONSTRAINT [FK_Book_Person] FOREIGN KEY([PersonCode])
REFERENCES [dbo].[Person] ([Code])
ON UPDATE CASCADE
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[Book] CHECK CONSTRAINT [FK_Book_Person]
GO

 

可以看到Person表和Book表是一对多关系,一个Person可以有多个Book,所以Book表的PersonCode列是外键,指向Person表的Code列,并为强制约束,也就是说Book表的PersonCode列的值,只能是Person表的Code列值,否则SQL Server会报错:

技术分享图片

 

现在我们执行下面语句给两张表插入数据,我们将插入Person表和Book表的两个Insert语句写在了个事务transaction中,按道理其中一个Insert执行失败,另一个就不会执行:

BEGIN TRAN

INSERT INTO Person([Code],[Name])
VALUES(P003,Jack)


INSERT INTO [dbo].[Book]([BookCode],[BookName],[PersonCode])
VALUES
(B001,B001,P003),
(B002,B002,P003),
(B003,B003,P003),
(B004,B004,P003),
(B005,B005,XXX)--由于Book表的[PersonCode]列值‘XXX‘在Person表的[Code]列中不存在,所以整个INSERT INTO [dbo].[Book]语句会报错不会执行

COMMIT

由于值"XXX"在Person表的[Name]列中不存在,所以INSERT INTO [dbo].[Book]语句报错没有执行,但是我们意外地发现INSERT INTO Person却随着事务Commit一起提交了。。。Person表的数据被成功插入了。。。

(1 行受影响)
消息 547,级别 16,状态 0,第 7 行
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Book_Person". The conflict occurred in database "TestDB", table "dbo.Person", column ‘Code‘.
The statement has been terminated.

查询Person表数据:

技术分享图片

查询Book表数据:

技术分享图片

这是因为INSERT INTO [dbo].[Book]语句虽然报错没执行,但是最下面的Commit语句却执行了,也就是说INSERT INTO [dbo].[Book]语句报错,并没有阻止后面Commit语句的执行,所以INSERT INTO Person语句随着事务被提交到数据库生效了。。。

 

现在我们更改上面的语句如下,将两个Insert语句都放到try catch中:

BEGIN TRAN

BEGIN TRY

    INSERT INTO Person([Code],[Name])
    VALUES(P003,Jack)


    INSERT INTO [dbo].[Book]([BookCode],[BookName],[PersonCode])
    VALUES
    (B001,B001,P003),
    (B002,B002,P003),
    (B003,B003,P003),
    (B004,B004,P003),
    (B005,B005,XXX)--由于Book表的[PersonCode]列值‘XXX‘在Person表的[Code]列中不存在,所以整个INSERT INTO [dbo].[Book]语句会报错不会执行


    COMMIT

END TRY
BEGIN CATCH

    ROLLBACK 

END CATCH

运行后,我们再查询Person表的数据:

技术分享图片

查询Book表数据:

技术分享图片

我们可以看到这次就和我们的预期一致了,在INSERT INTO [dbo].[Book]语句报错后,后面的Commit语句没有执行,执行了catch中的Rollback,最后两张表的数据都没有插入数据库。

 

SQL Server中事务transaction如果没写在try catch中,就算中间语句报错还是会提交

标签:primary   报错   ati   tran   off   get   server   插入数据   pdb   

原文地址:https://www.cnblogs.com/OpenCoder/p/9800638.html

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