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Re: [Gnumed-devel] Questions re database schema - normalization

From: Karsten Hilbert
Subject: Re: [Gnumed-devel] Questions re database schema - normalization
Date: Fri, 3 Sep 2004 10:03:56 +0200
User-agent: Mutt/

> >select.. natural join ..on ..  mechanism suggests
> >it's better to have a unique id name for each entity
> I think we have fields named simply "id" in some tables.
most, actually, and simply "pk" in the others

> Does this mean that
>    if a join should have to operate on 2 tables
>    selecting from each a field named "id"
> that the syntax will stumble
No. It is IMO advisable anyways (and in most case inavoidable)
to be explicit, eg. join on = or
=, eg qualified field names.

> and/or it is unwanted/extra work to 
> have to provide aliases so as to be able to distinguish the column 
> names and data from the two "id" fields in the output?
Doing a join on id doesn't automatically include that field in
the select list. IF both are in the select list, they should
be aliased appropriately (as we do profusely in views).

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