On Wednesday 09 June 2004 16:50, Amir Hardon wrote:
> Hi,
> I'm planning a DB structure for an e-commerce system, and facing some
> question about the DB efficiency that I don't know how to approach.
>
> For example what will be better, storing all items information in one table
> with one column for category, or having a separate items table for each
> category.
Doesn't having separate tables contradict one of the Relational Database Model
Normalization Rules (can't remember which)? Even if it doesn't, it seems like
a Bad Idea<tm> as far as modularity is concerned.
For once in an SQL statement, you can't select (AFAIR) a table based on the
value of a select statement. This:
SELECT *
FROM (SELECT table FROM categories WHERE cat_id = 5)
WHERE item_id = 103
won't work. (at least I think it won't.)
Another thing is that you have several tables with the same schema that you
need to update regularly.
That probably did not answer your question (even tough your guess seems
correct), but it triggered my opinion bit.
Regards,
Shlomi Fish
> My guess is that separate tables will be faster for use but will consume
> more disk space.
>
> Where can I learn about this subject? I guess it also depends on the DB
> backend I'm using, so for this case it is mySQL.
>
> Thanks,
> -Amir.
>
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Shlomi Fish [EMAIL PROTECTED]
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