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Normalization question
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General information
Forum:
Visual FoxPro
Category:
Other
Miscellaneous
Thread ID:
00149947
Message ID:
00149964
Views:
18
I'd like to stick to my guns and stay normalized whenever possible. However, in the event of having to include the calculated field (for speed issues), I certainly like the idea of the recalc utility. I hadn't considered that before.

>It's not generally a good idea to store any calculated data. The exception is when you need to be able to get at a value quickly that would take a long time to calculate on the fly but could easily be adjusted every time a value that affects the total is changed. This can be dangerous in a desktop database like VFP because it's actually possible for part of a trasaction to be completed if a user crashes while updating data. This means that the YTD field may not be accurate. You may want to add a utility to recalculate all of these values just in case.
>
>>When it comes to good normalization practice, is it better to not denormalize when attempting to store aggregate data? For example, what are the implications of deciding whether or not to have a "YTD purchased field" in a customer table? I've read that the decision to include this type of aggregate field is based on the need for speed, and therefore may necessitate including it in the customer table. I would like to hear some comments regarding this.
>>
>>FYI, thread #130522 was helpful with regards to some other normalization questions if anyone is interested.
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