根據條件使用觸發器鎖定某些行

Question

說例如，其中一個表具有某些行，如何根據等於true的條件阻止更新某些行，但是允許更新在所有行上提交條件是錯誤的。

採取這種例子，我通過中止整個事務

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 

如果一個人「鎖定」之前的所有行到2007年1月4日到運行以下命令：

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

交易將失敗，並出現錯誤：

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. 

是否有修改此觸發器以允許交易的方法ñ提交，但只有行日期是> 1/4/2007

這是一個非常簡短的例子（我使用的表格更復雜），如果我是誠實的，我認爲它更清潔如果整個交易失敗了，我只是好奇它是如何完成的。

Answer 1

您需要一個BEFORE aka INSTEAD OF trigger並僅過濾到允許的行。

未經測試：

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