Hi John,

>Let's assume for a moment that the data store is a tier. I have not read any substantive material that includes the data store as a tier. However, that does not make that issue fact or fiction. So, let's go with it.

Doesn't Visual Modeller and Rational Rose treat the data store as a tier, distinct from data services? I'm just asking......

>Since the definitions of the User, Business, and Data services are fairly well agreed upon, what would the requirements be for the data-store tier? Does any data store qualify? If so, a text file counts since a text file is a bona-fide data store.

Yup, yup.

>I think at a minimum, the data store has to support a language. Further, the powers of the language have to be served to the outside world by the data store tier. Clearly, this would knock out a text file.

In an n-tier (3+) design, nobody in their right mind would use DBFs and the Fox DBC for the data store. At that level, IMHO, VFP cursors are temporary data storage elements at best.