觸發兩張表

Question

我有一個有多個表的航班數據庫。我試圖做出觸發條件，拒絕在有維護請求的航班上插入或更新。如果要求維修飛機，則在這些時間之間不應有飛行。我得到的錯誤信息很好，但似乎我總是得到它。怎麼來的？在此先感謝，我總是感謝幫助。

alter trigger DateMaintenanceTrigger 
on Flight 
after update, insert 
as 
    select 
     m.StartDate, m.TargetEndDate, f.DepartureDateID 
    from 
     Maintenance.MaintenanceRequest as m 
    inner join 
     Flight as f on f.PlaneID = m.PlaneID 
    where 
     f.DepartureDateID < m.TargetEndDate 
     and f.DepartureDateID > m.StartDate 

    begin 
     raiserror ('Flight cannot take place on this maintentance date, plane not ready.', 16,1); 
     rollback transaction; 
     return 
    end; 
    go 


insert into Flight 
values (304, 3, 1, 200192, 1, '20160916 09:00:00 AM'); 

Answer 1

上述問題發生，因爲你缺少IF子句，你也與完整的飛行表，如果atlease一個符合飛行標準，你你會得到錯誤的加盟，即。爲正確執行則需要與inserted.PlaneID加入，而不是因爲我已經證明下面

alter trigger DateMaintenanceTrigger on Flight 
after update, insert 
as 
IF EXISTS (
select m.StartDate, m.TargetEndDate, f.DepartureDateID 
from Maintenance.MaintenanceRequest as m 
JOIN inserted as i 
ON i.PlaneID = m.PlaneID 
and i.DepartureDateID < m.TargetEndDate and i.DepartureDateID > m.StartDate 
) 
    begin 
     raiserror ('Flight cannot take place on this maintentance date, plane not ready.', 16,1); 
     rollback transaction; 
     return 
    end; 
    go 



insert into Flight values (304, 3, 1, 200192, 1, '20160916 09:00:00 AM'); 

Answer 2

我希望你解決它現在，但如果沒有，我可以盡力幫助。試着這樣做，我試着在本地只是一個真/假的查詢，它應該工作，只要你的查詢是好的，我不知道在哪裏是最正確的方式把回滾，現在我把它放在catch函數中，但可能在raiserror（）之前更好。

alter trigger DateMaintenanceTrigger 
on Flight 
after update, insert 
as 

BEGIN TRY 
    IF EXISTS(
     select 
      m.StartDate, m.TargetEndDate, f.DepartureDateID 
     from 
      Maintenance.MaintenanceRequest as m 
     inner join 
      Flight as f on f.PlaneID = m.PlaneID 
     where 
      f.DepartureDateID < m.TargetEndDate 
      and f.DepartureDateID > m.StartDate 
    ) 
    BEGIN 
     raiserror ('Flight cannot take place on this maintentance date, plane not ready.', 16,1); 
    END 
    ELSE 
    BEGIN 
     insert into Flight values (304, 3, 1, 200192, 1, '20160916 09:00:00 AM'); 
    END 
END TRY 
BEGIN CATCH 
    DECLARE @ErrorMessage NVARCHAR(4000); 
    DECLARE @ErrorSeverity INT; 
    DECLARE @ErrorState INT; 

    SET @ErrorMessage = ERROR_MESSAGE(); 
    SET @ErrorSeverity = ERROR_SEVERITY(); 
    SET @ErrorState = ERROR_STATE(); 

    rollback transaction; 

    RAISERROR (@ErrorMessage, 
       @ErrorSeverity, 
       @ErrorState 
       ); 
END CATCH;