>Markus-
>
>First off, shoot me if you must, but why does it matter that a business tier know it needs a primary key? I use INSERT INTO that needs a primary key. But my backend takes care of the primary key (stored procedure in the DBC). My muddle-tier (pun intended) just knows it needs a PK in order to proceed. But it doesn't care how it's assigned.
>
>So, I guess I'm still really unclear on encapsulation and denial. Meaning, why can't tiers "know" common sense stuff, like primary keys exist?
>
>BTW, I asked Travis for clarification on how his post related. I thank you for making that clear. :-)
>
>>>> Ok, lets think about the job responsibilities of the back-end in a
>>>> modern-day program: it is responsible for making sure its data ok.
>>>> Furthermore, it's NOT the job of the middle-tier to ensure that
>>>> your data is valid: like I said, that's the job of whatever back-end
>>>> you're using.
>>
>...snip


Hi Nancy!

Well, the problem I have with the middle-tier knowing about PKs is as follows: What if you decide to switch to a back end that's architecture is totally different and doesn't support primary keys, or that does primary keys totally different (such as in a scenario where you have to talk to data that's not yours...).

Markus