sql触发器怎样运用【MySQL教程】,sql触发器

sql中的触发器是对某个表举行操纵时而触发的某种前提，能够用CREATE语句建立触发器，DROP语句删除触发器，ALTER语句禁用触发器等

触发器

在SQL Server内里也就是对某一个表的肯定的操纵，触发某种前提，从而实行的一段顺序。触发器是一个特别的存储历程。

CREATE TRIGGER tr_update_Stock   --自动采购触发器
ON T_Product
FOR update
AS
IF (update(Stock)) --推断stock字段是不是更新
BEGIN
  --查询出库存低于下限的产物近一个月的消耗量
 --建立暂时表
 IF object_id('[tempdb].[dbo].##table1') IS NOT NULL --推断暂时表#tmp是不是存在,存在则删除
    DROP TABLE ##table1
            SELECT * INTO ##table1 FROM (SELECT row_number() OVER (ORDER BY ProductID) AS rowNo,c.ZNumber - c.Stock AS purchaseNum,* FROM (
 SELECT  ProductID,SUM(s.Numbers) ZNumber,p.Stock,SUM(s.OutMoney) ZMoney,p.Price 
 FROM [dbo].[T_StorageOut] t inner join[dbo].[T_StorageRelation] s 
 ON t.StorageOutID=s.StorageOutID inner join T_Product p ON s.ProductID=p.Id
 WHERE t.MakerTime between Convert(VARCHAR,DATEADD(MONTH,-1,GETDATE()),23) and Convert(VARCHAR,GETDATE(),23) and ProductID in (SELECT Id FROM V_ProductSupplierInfo where (Stock-StockLowerLimit)<0)
 GROUP BY ProductID,p.Stock,p.Price) c) ddd
--盘算用参数
DECLARE @purchaseNum INT,@Price NVARCHAR(50),@totalMoney NVARCHAR(50),@ZpurchaseTotal INT --采购数目,单价,总金额,总数目
SELECT @totalMoney = 0,@purchaseNum = 0,@Price = 0,@ZpurchaseTotal=0
 --采购单所需参数
  DECLARE @PurchaseNumber NVARCHAR(50),@DopurchaseId INT,@DopurchaseTime NVARCHAR(200),@PurchaseTotal INT,@PurchasePrice NVARCHAR(200),@PurchaseState INT,@PurchaseType INT
   SET @PurchaseNumber='JH'+replace(replace(replace(convert(VARCHAR,getdate(),120),'-',''),' ',''),':','') --进货单号JH20171031092322
--采购单概况所需参数 （产物id，产物采购价钱）
  DECLARE @StockProductId INT,@DPurchasePrice NVARCHAR(20)
--轮回用参数
DECLARE @curIndex INT,@rowCount INT
--推断用参数
DECLARE @OTCount INT,@PTCount INT    
SET @curIndex = 1
SELECT @rowCount = COUNT(1) FROM ##table1
IF(@rowCount>0)
BEGIN
   WHILE @curIndex <= @rowCount
   BEGIN
      --查询出第一行数据的采购数目，单价，产物id
      SELECT @purchaseNum = purchaseNum,@Price = Price,@StockProductId =ProductID FROM ##table1 WHERE rowNo = @curIndex
       --采购总金额
      SET @totalMoney = @totalMoney + @purchaseNum * CONVERT (INT,@price)
      --采购总数目
      SET @ZpurchaseTotal =@ZpurchaseTotal + @purchaseNum  
      --单个产物的采购金额 
      SET @DPurchasePrice=@purchaseNum * CONVERT (INT,@price)
      IF object_id('[tempdb].[dbo].#PTable') IS NOT NULL --推断暂时表#tmp是不是存在,存在则删除
       DROP TABLE #PTable
      IF object_id('[tempdb].[dbo].#OTable') IS NOT NULL --推断暂时表#tmp是不是存在,存在则删除
       DROP TABLE #OTable       
      --依据产物id查询出包括该产物的采购单已悉数审批
      SELECT * INTO #PTable FROM (SELECT PurchaseState FROM [dbo].[T_Purchase_Order] WHERE PurchaseNumber in(SELECT PurchaseOrderId FROM  [dbo].[T_Purchase_OrderDetails] WHERE StockProductId=@StockProductId) and PurchaseState=0) AS a
      --依据产物id查询出包括该产物的定单已悉数入库
      SELECT * INTO #OTable FROM (SELECT OrderState FROM T_Order WHERE OrderNumber in(SELECT OrderNumber FROM  T_OrderDetails WHERE ProductId=@StockProductId) and OrderState=0) AS c
      SELECT  @PTCount = COUNT(1) FROM #PTable
      SELECT  @OTCount = COUNT(1) FROM #OTable
          IF (@PTCount=0) --已悉数审批
          BEGIN
             IF(@OTCount=0) --=0示意包括该产物的定单均已入库，能够生成新的
              BEGIN
               INSERT INTO [dbo].[T_Purchase_OrderDetails] VALUES(@PurchaseNumber,@StockProductId,@purchaseNum,@DPurchasePrice)
              END
          END
      SET @curIndex = @curIndex + 1
   END
END
  set @DopurchaseId = 16646 --自动生成
  set @DopurchaseTime=Convert(NVARCHAR,getdate(),23)   --当前时候 2017-10-31
  set @PurchaseTotal =@ZpurchaseTotal
  set @PurchasePrice =@totalMoney
  set @PurchaseState =0 --未审核
  set @PurchaseType = 2 --自动生成 
  --变量赋值完成，对采购单做增加操纵
   IF (@PTCount=0)
   BEGIN
    INSERT INTO T_Purchase_Order VALUES(@PurchaseNumber,@DopurchaseId,@DopurchaseTime,@PurchaseTotal,@PurchasePrice,@PurchaseState,@PurchaseType)
   END
END

这是一个自动采购的触发器，重要须要注重的触发前提，以及暂时表的作用。

触发器的运用

建立触发器

CREATE TRIGGER tr_update_Stock

删除触发器

DROP  TRIGGER tr_update_Stock

禁用

ALTER TABLE trig_example DISABLE TRIGGER trig1
GO

恢复

ALTER TABLE trig_example ENABLE TRIGGER trig1
GO

禁用某个表上的一切触发器

ALTER TABLE 你的表 DISABLE TRIGGER all

启用某个表上的一切触发器

ALTER TABLE 你的表 enable TRIGGER all

禁用一切表上的一切触发器

exec sp_msforeachtable 'ALTER TABLE ? DISABLE TRIGGER all'

启用一切表上的一切触发器

exec sp_msforeachtable 'ALTER TABLE ? enable TRIGGER all'

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