Business Logic: Database or Application Layer

Question

The age old question. Where should you put your business logic, in the database as stored procedures ( or packages ), or in the application/middle tier? And more importantly

Answer 1

If you need database independence, you'll probably want to put all your business logic in the application layer since the standards available in the application tier are far more prevalent than those available to the database tier.

However, if database independence isn't the #1 factor and the skill-set of your team includes strong database skills, then putting the business logic in the database may prove to be the best solution. You can have your application folks doing application-specific things and your database folks making sure all the queries fly.

Of course, there's a big difference between being able to throw a SQL statement together and having "strong database skills" - if your team is closer to the former than the latter then put the logic in the application using one of the Hibernates of this world (or change your team!).

In my experience, in an Enterprise environment you'll have a single target database and skills in this area - in this case put everything you can in the database. If you're in the business of selling software, the database license costs will make database independence the biggest factor and you'll be implementing everything you can in the application tier.

Hope that helps.