Question

我需要一个基本的sql触发器的例子，现在我解释一下：

我有一个包含5列的表（column1，power，column3，column4，times）

“权力”的值实时变化（是数字），他的数据类型是“真实的” 而“times”的数据类型是'int'

我会触发每次“力量”增加0倍'1次

抱歉，如果我的英语不完美！并希望你理解我的意思！如果有什么不明确告诉我，我会尽力解释！：）

Answer 1

可能的基本触发器：

create trigger MyBasicTrigger on MyBasicTable
after insert, update
as
--  Trigger rowcount should not mess with update that triggered it, search for it in documentation provided here
   set NoCount ON
-- If power is mentioned in update/insert statement at all
   if update(Power)
   begin
   -- Update times for each changed row that has value of power 0
   -- Inserted table holds new values in updated rows
   -- You didn't mention your PK column(s), so I assume the name would be "ID"
      update MyBasicTable set Times = Times + 1
      from MyBasicTable inner join inserted on MyBasicTable.ID = inserted.ID
      where Inserted.Power = 0
   end

NoCount和更新（电源）的文档是here。

Answer 2

假设column1是主键，触发器的一般形式如下：

create trigger MyPower
on MyTable
after insert, update
as
  if exists (select column1 
             from inserted i join MyTable m
             on i.column1 = m.column1
             and i.power = 0)
    update MyTable set times = times + 1 
    where exists (select column1 from inserted i 
              join MyTable m
              on i.column1 = m.column1)

SQL Server触发器更新列值

2 个答案: