SQLトリガー - セットベースの操作でカーソルを変換する

Question

セットベースの操作の基本を理解しようとしています。私は読んでセットベースの操作は、カーソルのループよりもパフォーマンスがはるかに優れています。カーソルを設定操作に変換するにはどのような手順が必要ですか？あなたは私たちにもう少し詳細をお願いできます：ここで私は

CREATE Trigger DataUpdate ON [Data] 
    FOR UPDATE 
    AS 
     SET NOCOUNT ON 
    BEGIN 
     declare @Id int 
     declare cur cursor for select DataId from Deleted 
     open cur 
     fetch next from c into @Id 
     while @@FETCH_STATUS = 0 
      begin 
      if 
       UPDATE(ID) and 
       UPDATE(Title) or 
       UPDATE(Description)    
      BEGIN 
       update Data 
       set ModDate = getdate() 
       where ID = @Id 
      END 
      fetch next from c into @Id 
      end 
     close cur 
     deallocate cur 
    end 

、別のトリガー

CREATE TRIGGER DataAudit 
     ON [Data] FOR UPDATE 
     AS 

     SET NOCOUNT ON 

    IF UPDATE(ModDate) 
     BEGIN 
      SET NOCOUNT ON 
      DECLARE @ParentId INT 
      DECLARE @ChildId INT 
      DECLARE @Export BIT 

      DECLARE cursorInserted CURSOR FOR 
       select ParentID, ChildID, Export from INSERTED 

      OPEN cursorInserted 

      Fetch next from cursorInserted into @ParentId, @ChildId, @Export 

      WHILE @@FETCH_STATUS = 0 
      BEGIN    
       DECLARE @brief BIT 

       DECLARE cursorBriefcase CURSOR FOR 
       select ShowExport 
        from Sites 
       where SiteID in (select ds.siteid from DataSiteIDs as ds where ChildID = @ChildId) 

       OPEN cursorBriefcase 
       -- Perform the first fetch. 
       FETCH NEXT FROM cursorBriefcase INTO @brief 

       -- Check @@FETCH_STATUS to see if there are any more rows to fetch. 
       WHILE @@FETCH_STATUS = 0 and @brief = 0 
        BEGIN 
         FETCH NEXT FROM cursorBriefcase INTO @brief 
        END 
       CLOSE cursorBriefcase 
       DEALLOCATE cursorBriefcase 

      IF @brief = 0 and 
       @Export = 1 and 
       ((SELECT Distinct ParentID FROM Sites Where ParentID = @ParentId AND (TemplateID = 5 OR TemplateParams = 1)) > 0) and 
       ((Select Distinct ParentID From SubUserGroupIDs Where ParentID = @ParentId) > 0) 
      BEGIN 
       -- Populate the SubAuditItems table with rows on hold 
       INSERT INTO SubAuditItems (ChildID, ParentID, RecordDate, Type, FromTable) 
       VALUES (@ChildId, @ParentId, GETDATE(), 'MOD', 'Data') 
      END 

      Fetch next from cursorInserted into @ParentId, @ChildId, @Export 
      END 
      CLOSE cursorInserted 
      DEALLOCATE cursorInserted  

     END 

Answer 1

@Yusufで働いているカップルの例はありますか？達成したいことは何ですか？

CREATETRIGGER [dbo].[UpdateCustomerHistory] 
    ON [dbo].[tblCustomers] 
AFTER DELETE 
AS 

--------------------------------------------------- 
-- Insert the deleted Record in History 
--------------------------------------------------- 
INSERT INTO tblCustomersHistory 
(
    CustomerId, Name, DateCreated 
) 
------ Get deleted row 
SELECT CustomerId, Name, GETDATE() 
FROM DELETED 

Answer 2

これは、最初のトリガの体のために行う必要があります：私が正しくあなたの第二の例を解釈している場合は

UPDATE d     
SET ModDate = getdate() 
FROM inserted i 
JOIN data d ON i.id = d.ID 
JOIN deleted del ON i.id = del.id 
WHERE 
    (i.Id <> del.id) 
OR 
    (i.title <> del.title) 
OR 
    (i.description <> del.description) 

を使用すると、表から削除されたレコードを維持したい場合、あなたはそれが好き行うことができます

INSERT INTO SubAuditItems (ChildID, ParentID, RecordDate, Type, FromTable) 
SELECT i.ChildID,i.ParentID, GETDATE(), 'MOD', 'Data' 
FROM INSERTED 
JOIN DataSiteIDs s ON ds.childid = i.childid 
JOIN Sites s ON ds.siteid = s.siteid 
WHERE i.Export = 1