Domain Logic and SQL (martinfowler.com)

'One of the first questions people consider with this kind of thing is performance. Personally I don't think performance should be the first question. My philosophy is that most of the time you should focus on writing maintainable code. Then use a profiler to identify hot spots and then replace only those hot spots with faster but less clear code'

'multi-user scenarios often cause surprising changes to the way queries behave, so real profiling has to be done under a realistic multi-user load. You may find that locking issues outweigh anything you can get by faster individual queries.'

Another article on the same: http://www.vertabelo.com/blog/notes-from-the-lab/business-lo...