根据条件使用触发器锁定某些行

Question

说例如，其中一个表具有某些行，如何根据等于true的条件阻止更新某些行，但是允许更新在所有行上提交条件是错误的。

采取这种例子，我通过中止整个事务

SET ANSI_NULLS ON 
GO 
SET QUOTED_IDENTIFIER ON 
GO 
SET ANSI_PADDING ON 
GO 
CREATE TABLE [dbo].[tbl_TriggerTest] (
    [ID] [int] IDENTITY(1,1) NOT NULL, 
    [Value] [varchar](25) NULL, 
    [Date] [datetime] NULL, 
CONSTRAINT [PK_tbl_TriggerTest] 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 ANSI_PADDING OFF 
GO 
SET IDENTITY_INSERT [dbo].[tbl_TriggerTest] ON 

GO 
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (1, N'12', CAST(0x0000979A00000000 AS DateTime)) 
GO 
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (2, N'13', CAST(0x00009A7500000000 AS DateTime)) 
GO 
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (3, N'14', CAST(0x00009BE200000000 AS DateTime)) 
GO 
INSERT [dbo].[tbl_TriggerTest] ([ID], [Value], [Date]) VALUES (4, N'4', CAST(0x00009D4F00000000 AS DateTime)) 
GO 
SET IDENTITY_INSERT [dbo].[tbl_TriggerTest] OFF 
GO 
CREATE TRIGGER [dbo].[LockOldWelshRows] ON [dbo].[tbl_TriggerTest] 
    FOR UPDATE 
AS 
    BEGIN 
     DECLARE @Count INT 
     SELECT @Count = COUNT([ID]) 
     FROM INSERTED 
     WHERE [Date] < CONVERT(DATETIME, '01/04/2007 00:00:00', 103) 

     IF @Count > 0 
      BEGIN 
       RAISERROR('Rows prior to 01/04/2007 are locked',16,1) 
       ROLLBACK TRANSACTION 
       RETURN ; 
      END 
    END 

GO 

如果一个人“锁定”之前的所有行到2007年1月4日到运行以下命令：

UPDATE [tbl_TriggerTest] SET [Value] = [Value] + 'M' 

交易将失败，并出现错误：

Msg 50000, Level 16, State 1, Procedure LockOldWelshRows, Line 12 
Rows prior to 01/04/2007 are locked 
Msg 3609, Level 16, State 1, Line 1 
The transaction ended in the trigger. The batch has been aborted. 

是否有修改此触发器以允许交易的方法ñ提交，但只有行日期是> 1/4/2007

这是一个非常简短的例子（我使用的表格更复杂），如果我是诚实的，我认为它更清洁如果整个交易失败了，我只是好奇它是如何完成的。

Answer 1

您需要一个BEFORE aka INSTEAD OF trigger并仅过滤到允许的行。

未经测试：

CREATE TRIGGER [dbo].[LockOldWelshRows] ON [dbo].[tbl_TriggerTest] 
    INSTEAD OF UPDATE 
AS 
    BEGIN 

     UPDATE 
     T 
     SET 
     T.SomeCol = I.SomeCol... 
     FROM 
     [dbo].[tbl_TriggerTest] T 
     JOIN 
     INSERTED I ON T.keycol = I.keycol 
     WHERE 
     T.[Date] >= '20070401'; 

    END 

GO