Hi everybody,

I wrote the following trigger that updates the table itself among other tasks. Suprisingly it works and doesn't go into the infinite loop. Can someone please explain how does it work?

create trigger SR_tr_UPDATE on Student_Registration after update 
as
  begin
     declare @Status char(1)
     select @Status = Status from Inserted
     if @Status = 'D'
        begin  
        update Student_Registration set Drop_Date = getdate() 
        from Student_Registration SR, Inserted I 
        where SR.SID = I.SID and SR.TermID = I.TermID

        update Student_Summary set NumOfCourses = NumOfCourses - 1
        from Student_Summary SS inner join Inserted I on 
        SS.SID = I.SID

        update Course_Summary set NumberOfStudents = NumberOfStudents - 1
        from Inserted I, Course_Term CT, Course_Summary CS 
        where  I.TermID = CT.TermID and (CS.cYear = CT.cYear and CS.cID = CT.cID)
       end
   else
    begin
      print 'Invalid Status'
      rollback tran
   end
end

Thanks a lot in advance.