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Re: Subquery in constraints...

From: Vadim Tropashko <vadimtro_at_yho.cm>
Date: Mon, 11 Oct 2004 12:38:57 -0700
Message-ID: <mxBad.44$UF1.123@news.oracle.com> 





Mikito Harakiri wrote:


> Suppose you implement foreign key constraint as a subquery in the check

> constraint clause. Would the DBMS be smart enough to leverage existing index

> on the parent_id column? 




What is so difficult about it? Checking if parent record exist is just a 
[recursive] query. SQL optimiser must be perfectly able to decide 
whether to use index or not.
Received on Mon Oct 11 2004 - 14:38:57 CDT












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