Hugh,
I'm certainly no expert on this matter, but I think VFP falls down on this point:
Although non-relational tools are allowed, it must be possible to manage the database using only relational tools, and the non-relational tools must not be allowed to bypass the integrity constraints imposed by the relational tools.For example, primary key uniqueness is maintained by an index in VFP. There are ways to open tables from outside VFP, without the index, and create duplicate primary keys. Referential integrity can be broken by similar means.
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>Please educate me on this topic. I'm confused. Specifically what does Visual FoxPro have (or not have) that precludes it from being a relational database management system (RDBMS) in your opinion?
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http://coral.lili.uni-bielefeld.de/EAGLES/WP5/termdeliv97/node38.html>
Steve Gibson