Question

我想创建一个Trigger来更新列

dbo.tbl_dispatching.Actual_Pickup_Time

当下面的列更新为5

时，带有时间戳的

dbo.tbl_dispatching.Status_ID = "5"

并更新

dbo.tbl_dispatching.Actual_Delivery_Time

当下面的列更新为8

时，带有时间戳的

dbo.tbl_dispatching.Status_ID = "8"

到目前为止我已经这样做了，不知道如何完成它：

CREATE TRIGGER Delay_Timestamp ON [dbo].[tbl_dispatching] 
FOR UPDATE
AS
    declare @DispatchingID int; --Primery Key of Dispatching_ID
    declare @Statusid int;
    declare @Actual_Pickup_Time datetime;
    declare @Actual_Delivery_Time datetime;
    declare @audit_action varchar(100);

select @DispatchingID=i.dispatching_id from inserted i; --Primery Key of Dispatching_ID
select @Statusid=i.Status_ID from inserted i; 
select @Actual_Pickup_Time=i.Actual_Pickup_Time from inserted i; 
select @Actual_Delivery_Time=i.Actual_Delivery_Time from inserted i;   

if @StatusID = (5)
    set @Actual_Pickup_Time=GETDATE();
if  @StatusID = (8)
    set @Actual_Delivery_Time=GETDATE();

update set tbl_Dispatching(Actual_Pickup_Time,Actual_Delivery_Time) 
values (@Actual_Pickup_Time,@Actual_Delivery_Time) where dispatching_id = @DispatchingID
go

这会有用吗？

Answer 1

您的根本缺陷是，您似乎希望触发器每行一次 - 这在SQL Server中是 NOT 。相反，触发器会在每个语句时触发，并且伪表Inserted和Deleted可能包含多行。

在这种情况下，这个作业

select @Statusid=i.Status_ID from inserted i;

将从Inserted表中选择一行任意行，忽略所有其他行 - 通常不是您想要的。

您需要以基于集合的方式重写触发器 - 不要指望Inserted和Deleted只包含一行 - 他们不会！

您需要使用以下代码：

CREATE TRIGGER Delay_Timestamp ON [dbo].[tbl_dispatching] FOR UPDATE AS -- Update Actual_Pickup_Time if "Status_ID" has changed to 5 UPDATE disp SET Actual_Pickup_Time = SYSDATETIME() FROM dbo.tbl_Dispatching disp INNER JOIN Inserted i ON i.DispatchId = disp.DispatchId -- use PRIMARY KEY of table! INNER JOIN Deleted d ON d.DispatchId = disp.DispatchId -- use PRIMARY KEY of table! WHERE i.Status_ID = 5 -- new value is 5 AND d.Status_ID <> 5 -- old value was NOT 5 -- Update Actual_Delivery_Time if "Status_ID" has changed to 8 UPDATE disp SET Actual_Delivery_Time = SYSDATETIME() FROM dbo.tbl_Dispatching disp INNER JOIN Inserted i ON i.DispatchId = disp.DispatchId -- use PRIMARY KEY of table! INNER JOIN Deleted d ON d.DispatchId = disp.DispatchId -- use PRIMARY KEY of table! WHERE i.Status_ID = 8 -- new value is 8 AND d.Status_ID <> 8 -- old value was NOT 8

SQL - 更新后触发器 - 如何在列值更改为特定值时添加时间戳

1 个答案: