Help required for UPDATE TRIGGER
 

Hi all,

I have created the Trigger for UPDATING to be invoked when Returnedon column is updated using the following code snnipet.

CREATE TRIGGER trg_ForUpdateOnBookIssuedDetails

on BOOKISSUEDDETAILS

For update

as begin

declare @Rows1 int,@Rows2 int

if(update(ReturnedOn))



begin

begin tran

update nur

set nur.NumberOfBooksIssued = nur.NumberOfBooksIssued -1

from NewUserRegister nur inner join INSERTED i

on i.IssuedTo=nur.UserName



set @Rows1 = @@RowCount



update lbd set Inventory = Inventory +1

from LIBRARYBOOKDETAILS lbd inner join

inserted i on lbd.BookID = i.BookId



set @Rows2 = @@rowcount



if @Rows1 * @rows2 >0

commit tran

else

begin

raiserror('Error Updating the Database',16,-1)

rollback tran

end

end

end

Now I want To perform this Updation only if the RETURNEDON column is null. If the ReturnedOn column consists of some other value then the Updation of records should not take place.

Can anyone help me out in performing this task?

Please help me out.

Thanks in advance!!

Re: Help required for UPDATE TRIGGER
 

Try to change:

if(update(ReturnedOn))

To:

IF (SELECT ReturnedOn FROM INSERTED) IS NULL