SQL Server触发器

浏览数：22 / 时间：2015年06月12日

CREATE TRIGGER trTask_Update ON 
dbo.Task
    FOR 
UPDATE
AS
    BEGIN
 
        DECLARE 
@TaskId INT
        DECLARE 
@NewTaskOrder INT
        DECLARE 
@WorkstreamId INT
        DECLARE 
@OldTaskOrder INT
 
--update
        BEGIN
            SELECT  
@TaskId = id ,
                    @OldTaskOrder = TaskOrder ,
                    @WorkstreamId = WorkstreamId
            FROM    
deleted
 
            SELECT  
@NewTaskOrder = TaskOrder
            FROM    
dbo.Task
            WHERE   
Id = @TaskId
--When updating a row, if old value is greater than new value, then +1 all values that are >= the new value and < the old value
            IF @OldTaskOrder > @NewTaskOrder 
                BEGIN
                    UPDATE  
dbo.Task
                    SET     
TaskOrder = TaskOrder + 1
                    WHERE   
WorkstreamId = @WorkstreamId
                            AND 
TaskOrder >= @NewTaskOrder
                            AND 
TaskOrder < @OldTaskOrder
                            AND 
Id <> @TaskId
                END
     
            IF @OldTaskOrder < @NewTaskOrder 
                BEGIN                    
                                 
                    UPDATE  
dbo.Task
                    SET     
TaskOrder = TaskOrder - 1
                    WHERE   
WorkstreamId = @WorkstreamId
                            AND 
TaskOrder <= @NewTaskOrder
                            AND 
TaskOrder > @OldTaskOrder
                            AND 
Id <> @TaskId
                END
 
        END
 
 
    END

CREATE TRIGGER trTask_Insert ON 
dbo.Task
    FOR 
INSERT
AS
    BEGIN
 
        DECLARE 
@TaskId INT
        DECLARE 
@NewTaskOrder INT
        DECLARE 
@WorkstreamId INT
        DECLARE 
@OldTaskOrder INT
  
--insert
        BEGIN
            SELECT  
@TaskId = id ,
                    @NewTaskOrder = TaskOrder ,
                    @WorkstreamId = WorkstreamId
            FROM    
INSERTED
--When inserting a new,+1 to all task orders that are equal to or greater than the newly inserted task‘s task order
            UPDATE  
dbo.Task
            SET     
TaskOrder = TaskOrder + 1
            WHERE   
WorkstreamId = @WorkstreamId
                    AND 
TaskOrder >= @NewTaskOrder
                    AND 
Id <> @TaskId
     
        END
 
    END

3.如何调试触发器：

一、打开SQL查询分析器
二、将以下Sql语句复制到查询窗口并运行
use pubs

CREATE trigger trigger_update on authors
for update
as
begin
print(‘update lastname=hoho‘)
end

CREATE proc Authors_procInsert
as
begin
update authors set au_lname=‘HOHO‘ where au_id=‘172-32-1176‘
end

三、在左边的对象浏览器中选择pubs->存储过程在Authors_procInsert(如未出现请刷新pubs数据库）上右击‘Execute stored procedure’，设置参数点击确定打开生成的执行存储过程的脚本 -> 点击SQL Server Management 菜单上的Debug -> Start Debugging...
四、当运行到" update authors set au_lname=‘HOHO‘ where au_id=‘172-32-1176‘“时按“F11”即进入触发器代码

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SQL Server触发器