SQL触发器

Question

如果更新为tbl_repair_visit.TENANTSATISFACTION = 'Poor'，我有附加的触发器。

的问题，如果我们改变了工程师命名工程师列更新，并且触发再次运行我有，如果TENANTSATISFACTION = 'Poor'

我如何设置这在所有只运行，如果TENANTSATISFACTION = 'Poor'列被更新和ignor更新其他列

ALTER TRIGGER [dbo].[tr_CustomerSatisfactionAlertRepair] 
    ON [dbo].[tbl_repair_visit] 
AFTER UPDATE 
AS 
BEGIN 
    SET NOCOUNT ON; 
    INSERT alertmessagedata (TypeID, Contract, Address, ORDERID, 
       ENGINEERS, Sent, DateAdded) 
    SELECT '5', tbl_property.contract, tbl_property.fulladdress, 
      tbl_repair_visit.orderid, tbl_repair_visit.engineer, 
      0, GETDATE() 
    FROM TBL_REPAIR_VISIT 
    INNER JOIN 
     INSERTED X ON TBL_REPAIR_VISIT.VISITID = X.VISITID 
    INNER JOIN 
     TBL_PROPERTY ON TBL_REPAIR_VISIT.PROPREF = TBL_PROPERTY.PROPREF 
    WHERE tbl_repair_visit.TENANTSATISFACTION = 'Poor' 
END 

Answer 1

在触发更新，你可以检查一列正在更新：

IF UPDATE（TENANTSATISFACTION） BEGIN .... END

Answer 2

我不认为你可以指定。触发器UPDATE，DELETE和INSERT在表中执行UPDATE，DELETE或INSERT（可选）时触发。

您可以按照Mike K.的建议进行操作，并检查您感兴趣的列是否已更改。

Answer 3

你不能用嵌套的触发器选项做些什么吗？
（设置该选项关闭，以便触发器不会导致其他触发器被触发）

或者，也许你可以创建一个INSTEAD OF触发器，而不是AFTER触发器。 Offcourse，然后在你的INSTEAD OF触发器中，你还必须编写UPDATE（或insert）语句，该语句应该执行实际的更新或插入到附加逻辑旁边的表中。

Answer 4

如果连接表（即插入）具有空值，则表示要检测更改的字段已更改，则将旧版本的记录新版本左连接。在触发BL的恶果

create table family 
(
id int not null identity(1,1), 
name varchar(100) not null, 
age int not null 
); 


insert into family(name,age) values('Michael', 32); 
insert into family(name,age) values('Matthew', 23); 



create trigger TrigUpdOnFamily on family 
for update 
as 

    if exists 
     (
     select * from deleted 
     left join inserted on inserted.id = deleted.id  

     -- put the fields to detect here... 
     and inserted.age = deleted.age 
      -- ...detections 
     where inserted.age is null) begin  

     -- detect important fields 
     print 'age change'; 

    end 
    else begin 
     -- ignore non-important fields 
     print 'nothing change'; 
    end; 

go 


-- possible SqlCommand from .NET 
update family set name = 'Michael', age = 20 where id = 1;  

update family set name = 'Mateo', age = 23 where id = 2; 

Answer 5

create table Programmer 
(
id int not null identity(1,1), 
name varchar(100) not null, 
status varchar(20) 
); 


insert into Programmer(name,status) values('Pampers', 'Rich'); 




create trigger TrigUpdOnProgrammer on Programmer 
for update 
as 

    if exists 
     (
     select * from deleted 
     left join inserted on inserted.id = deleted.id  

     -- put the fields to detect here... 
     and inserted.status = deleted.status -- detect if changed 
     -- ...detections 
     where inserted.status is null) 

     -- if changes detected on status, then check if it is Poor. 
     -- don't worry, there's no performance degradation. SQL AND is short-circuited 
     and exists(select * from inserted where status = 'Poor') 
    begin  
     print 'status changed'; 
    end 
    else begin 
     print 'changes ignored'; 
    end; 

go 

-- execute the following on succession, then check the output 

update Programmer set status = 'Poor' where id = 1; -- changes detected 

update Programmer set status = 'Poor' where id = 1; -- changes ignored 

update Programmer set status = 'Rich' where id = 1; -- changes ignored 

update Programmer set status = 'Poor' where id = 1; -- changes detected