Re: Join types

From: JOG <>
Date: Fri, 25 Jan 2008 09:19:54 -0800 (PST)
Message-ID: <>

On Jan 25, 11:04 am, Gints Plivna <> wrote:
> I'm a bit studying join types and trying to make a visualisation of
> relations among them. As a result I've created an ER diagram
> describing relations among them and it can be found here
> I've tried to find something like that using google however the best I
> could get was textual description. I'm not mathematician and studied
> set theory a bit 10 years ago in university and almost all have no
> forgotten :) so maybe it has some problems from set theory viewpoint.
> So question is - is it generally ok? If you know anything similar
> please add link either here or in my blog post. All comments welcome!
> Thanks!
> Gints

Having only looked at your breakdown briefly, I can't give you much comment (although I thought your time-bomb discussion of natural joins was entertaining). However, I would say that in general I view natural joins, equi-joins, etc. as specializations of the generalized theta join. I'd be interested if other's share this perspective. Received on Fri Jan 25 2008 - 18:19:54 CET

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