sybase更新觸發器 - 檢查多個行以進行更新

Question

我正在Sybase ASE數據庫中寫入觸發更新的觸發器，並比較更新前後的值。我這樣做來驗證更新是否實際更改了數據。如果是這樣的話，它會在監控表中添加一行。不幸的是，觸發器只有在更新命令隻影響1行時纔有效。如果影響多行我得到這個錯誤：

Msg 512, Level 16, State 5: 
Server 'myserver', Procedure 'myproc', Line 2: 
Subquery returned more than 1 value. This is illegal when the subquery follows =, !=, <, <= , >, >=, or when the subquery is used as an expression. 

我PROC看起來是這樣的：

create trigger mytrigger on mytable for update as 

set nocount on 

/* now do the insert if colum was updated */ 
if update(col_a) and (select col_a from inserted) not in (select col_a from deleted) 
begin 
    insert into monitoring_table (login,tablename,field,action,pstamp) 
     select suser_name(),'mytable','col_a','U',getdate() from inserted 
end 
/* now do the insert if colum was updated */ 
if update(col_b) and (select col_b from inserted) not in (select col_b from deleted) 
begin 
    insert into monitoring_table (login,tablename,field,action,pstamp) 
     select suser_name(),'mytable','col_b','U',getdate() from inserted 
end 
go 

任何想法如何，我可以得到我的周圍觸發器中這種多更新的問題？

Answer 1

如果錯誤是觸發那麼下面應該工作：而不是 ：

if update(col_a) and (select col_a from inserted) not in (select col_a from deleted) 

使用

if update(col_a) and exists (select col_a from inserted where col_a not in (select col_a from deleted)) 

Answer 2

這應該工作：

create trigger mytrigger on mytable for update as 

set nocount on 

/* now do the insert if colum was updated */ 
if update(col_a) and (select col_a from inserted where col_a not in (select col_a from deleted) 
begin 
    insert into monitoring_table (login,tablename,field,action,pstamp) 
     select suser_name(),'mytable','col_a','U',getdate() from inserted 
end 
/* now do the insert if colum was updated */ 
if update(col_b) and (select col_b from inserted where col_b not in (select col_b from deleted) 
begin 
    insert into monitoring_table (login,tablename,field,action,pstamp) 
     select suser_name(),'mytable','col_b','U',getdate() from inserted 
end 
go