>I've always developed single-tier FP/VFP apps. I've been meaning to try out some C/S stuff for at least two years (honest!), but now it looks like I should go straight to three tier for the in-house project we'll be starting in a few months. So I have a couple of questions.
>
>First, can anyone point me to the incurably self-taught programmer's guide to 3-tier development, if there is one?
>
>Second, can anyone answer a couple of very basic questions:
>
>1. When we say that the back end handles integrity, do we really mean only relational integrity? No business rules and no triggers? To me and my single-tier background, integrity was always synonymous with FP-style validation. That is, it handles relational integrity, business rules, and triggers that run after a user changes a value.
>
>2. The middle tier is for business rules, then, right? Such as, can't save the sales order if the customer is over credit limit. Also, the triggers go here? Such as, user has entered a sales tax code, recalculate the total value of the sales order.
>
>3. Finally, then, the front end is just to submit queries and updates to the middle, and report middle-layer errors to the user?
>
>As always, TIA...

There is an article by Robert Green, "Building Three-Tier Client/Server Applications with Visual FoxPro" on MSDN.

http://msdn.microsoft.com/library/techart/msdn_bko01.htm

HTH