Database container & persisten relations

[StewartUK]

Dear All,

I've recently been looking into the database container. I was interested to note from thread184-27200 (Sep 2000) that a number of programmers (BlindPete, ChrisRChamberlain, FoxDev and csr) are avoiding the container. For those who contributed to that - could you let me know, is this still the case?

My other question was - What are persistent relations actually FOR??? I had thought they were used for SQL selections but, from my short experimentation, this doesn't seem to be the case?

Any advice would be welcome, thanks

Stewart

 

[rgbean]

Stewart,
The most important reason for using a DBC and using persistant relationships, is for referential integrity. Properly implemented, using RI can simplify code not only in the ADD/DELETE/EDIT mode, but also in the queries when you don't have to worry about coding around "bad" data.

Rick

 

[IanWh]

The ability to use transactions is also a powerful feature of DBCs.

Having looked at thread you mentioned it seams that the contributors had tried out DBCs, had problems and then given up!

DBCs are a very powerful, and in my opinion, essential part of VFP. With all the added features I can't see why anyone wouldn't use them!

You must be mad!!

Ian

 

[rgbean]

Good catch Ian, I use transactioning so transparently (part of the framework), that I sometimes forget that it's in use. But you are right about it being "essential".

Rick

 

[foxdev]

I'll admit that my judgement is colored by the fact that, for the last several years, I've been developing in purely client-server environments. While there were a few local tables (mostly for multi-language support), the vast majority of the data resided on database servers. We were forced to use DBCs, because of our (supposed) requirements for updateable remote views. I (and the rest of my team) would have avoided DBCs had we had the opportunity.

However, if I was developing a system that only used native DBFs, I would use DBCs for the RI benefits, assuming there was no substantial performance hit. Robert Bradley

http://www.agrainofhope.org

http://www.lowcostprints.com

http://www.foxdev.com