Re: How are foreign key constraints built?

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От Greg Stark
Тема Re: How are foreign key constraints built?
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Msg-id 873bwq7vm6.fsf@stark.xeocode.com
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Ответ на Re: How are foreign key constraints built?  ("Jim C. Nasby" <decibel@decibel.org>)
Ответы Re: How are foreign key constraints built?  ("Jim C. Nasby" <decibel@decibel.org>)
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"Jim C. Nasby" <decibel@decibel.org> writes:

> Well, every other database I've used can do index covering, which means
> index scans *are* faster.

Still not necessarily true. In a case like this it would still be random
access which would be slower than sequential access.

Though Oracle is capable of taking the best of both worlds and doing a hash
join but taking the data from sequentially reading the index instead of the
table.

--
greg

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