I was creating a stored procedure and i got stuck in the writing methodology of me and my collegue.

I am using SQL Server 2005

1. I was writing Stored procedure like this

   BEGIN TRAN BEGIN TRY INSERT INTO Tags.tblTopic (Topic, TopicCode, Description) VALUES(@Topic, @TopicCode, @Description)

           INSERT INTO Tags.tblSubjectTopic
               (SubjectId, TopicId)
               VALUES(@SubjectId, @@IDENTITY)
         COMMIT TRAN
   END TRY
   
   
   BEGIN CATCH
           DECLARE @Error VARCHAR(1000)
           SET @Error= 'ERROR NO : '+ERROR_NUMBER() + ', LINE NO : '+ ERROR_LINE() + ', ERROR MESSAGE : '+ERROR_MESSAGE()
           PRINT @Error
           ROLLBACK TRAN
   END CATCH
   

2. And my collegue was writing it like the below one

   BEGIN TRY BEGIN TRAN INSERT INTO Tags.tblTopic (Topic, TopicCode, Description) VALUES(@Topic, @TopicCode, @Description)

           INSERT INTO Tags.tblSubjectTopic
               (SubjectId, TopicId)
               VALUES(@SubjectId, @@IDENTITY)
      COMMIT TRAN
   END TRY
   
   
   BEGIN CATCH
           DECLARE @Error VARCHAR(1000)
           SET @Error= 'ERROR NO : '+ERROR_NUMBER() + ', LINE NO : '+ ERROR_LINE() + ', ERROR MESSAGE : '+ERROR_MESSAGE()
           PRINT @Error
           ROLLBACK TRAN
   END CATCH
   

Here the only difference that you will find is the position of writing Begin TRAN. According to me the methodology of my collegue should not work when an exception occurs i.e. Rollback should not get executed because TRAN does'nt have scope. But when i tried to run both the code, both was working in the same way.

I am confused to know how does TRANSACTION works. Is it scope free or what ?