I am developing middle tier application for a long time, but since .NET i try to prevent to build middle tiers where ever it is possible. I have seen too many projects with 30% or more of the project budget is going ( or wasted?) into a middle tier.
Its cost a lot of money, make it more complex and often ends with a never ending story.
I must say you, i am developing web applications!
Why do the developer/architect the data layer/business layer choice?
- they think its cool and it is a must
- they think on performance
- they think on reuse
I don't not want to say, never use middle tier!
Anyway in ASP.NET 2.0 i have learned a concept which is called Provider Patterns. Take a look at the great Security Controls and how it works without coding. Providers are not new. I am sure you know the OLDEB Provider which comes after the great ODBC. The point is to be able to change the provider without change the business logic=code. After some research in the web i found an article from rob howard about the provider patterns and the idea to use it in .NET 1.1. The article is not easy to read and some things are missing, but its a excellent hint.
Yes and this is the topic about which i am talking on Advanced Developers Conference in November. I have never been before on this event. As the website looks like its more an architect event.