SQL Server 事务与锁

时间：2019-02-02 17:18:07 阅读：288 评论：0 收藏：0 [点我收藏+]

标签：upd script ESS class const alt ber compute begin

事务

事务就是作为一个逻辑工作单元的SQL语句，如果任何一个语句操作失败那么整个操作就被失败，以后操作就会回滚到操作前状态，或者是上个节点。为了确保要么执行，要么不执行，就可以使用事务。而锁是实现事务的关键，锁可以保证事务的完整性和并发性。

技术图片

代码实例

USE [MyDataBase]
GO
/****** Object:  Table [dbo].[Money]    Script Date: 2019/2/2 17:07:03 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Money](
    [ID] [bigint] IDENTITY(1,1) NOT NULL,
    [Name] [nvarchar](50) NOT NULL,
    [Money] [decimal](18, 0) NOT NULL,
 CONSTRAINT [PK_tb_Money] 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
SET IDENTITY_INSERT [dbo].[Money] ON 

INSERT [dbo].[Money] ([ID], [Name], [Money]) VALUES (1, N‘张三‘, CAST(1000 AS Decimal(18, 0)))
INSERT [dbo].[Money] ([ID], [Name], [Money]) VALUES (2, N‘李四‘, CAST(1000 AS Decimal(18, 0)))
SET IDENTITY_INSERT [dbo].[Money] OFF

数据库脚本

技术图片

BEGIN TRAN Tran_Money;
    --开始事务
  DECLARE @tran_error INT;
  SET @tran_error = 0;
  BEGIN TRY 
    UPDATE  dbo.Money
    SET     Money = Money - 30
    WHERE   Name = ‘张三‘;
    SET @tran_error = @tran_error + @@ERROR;
        --测试出错代码，看看张三的钱减少，李四的钱是否会增加
        --SET @tran_error = 1;
    UPDATE  dbo.Money
    SET     Money = Money + 30
    WHERE   Name = ‘李四‘;
    SET @tran_error = @tran_error + @@ERROR;
  END TRY

  BEGIN CATCH
    PRINT ‘出现异常，错误编号：‘ + CONVERT(VARCHAR, ERROR_NUMBER()) + ‘,错误消息：‘
        + ERROR_MESSAGE();
    SET @tran_error = @tran_error + 1;
  END CATCH;

  IF ( @tran_error > 0 )
    BEGIN
        --执行出错，回滚事务
        ROLLBACK TRAN;
        PRINT ‘转账失败，取消交易!‘;
    END;
  ELSE
    BEGIN
        --没有异常，提交事务
        COMMIT TRAN;
        PRINT ‘转账成功!‘;
    END