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Re: Pizza Example

From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Sun, 18 Apr 2004 11:19:30 GMT
Message-ID: <6vtgc.75876$FW4.5133412@phobos.telenet-ops.be>


Anthony W. Youngman wrote:
> In message <h2jdc.64877$%m6.4324481_at_phobos.telenet-ops.be>, Jan Hidders
> <jan.hidders_at_REMOVETHIS.pandora.be> writes
>

>> Dawn M. Wolthuis wrote:
>>
>>>  So, if "the Pizza has Mozzarella and Parmesan cheese" is stored as:
>>>  Pizza  Mozzarella
>>>           Parmesan
>>>  in a single, uh, record, then if the ordering is unwittingly useful, we
>>> didn't harm that ordering.
>>
>>
>> Indeed, but you did make certain query-optimizations impossible. Never 
>> mind that what you are advocating is basically sloppy data modelling.
>>

> What optimisations?

Certain join reorderings. Joins on lists are not commutative.

> Okay, Pick forces more stuff into the conscious
> design of the db programmer, but an index on cheese and I don't see what
> queries can't be optimised.

That doesn't surprise me.

Received on Sun Apr 18 2004 - 06:19:30 CDT

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