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	Thu, 27 Aug 2015 07:03:38 -0700 (PDT)
Date:	Thu, 27 Aug 2015 16:03:33 +0200
From:	"Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] pcb file format
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	<20150825022302 DOT 21819 DOT qmail AT stuge DOT se>
	<20150827131624 DOT GC8319 AT cuci DOT nl>
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An N:N grow to the square of number of items. A sorted table for example may be searched log(N) iterations which make a huge different then number of items grow.


On Thu, 27 Aug 2015 15:16:24 +0200
"Stephen R. van den Berg (srb AT cuci DOT nl) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com> wrote:

> Peter Stuge (peter AT stuge DOT se) [via geda-user AT delorie DOT com] wrote:
> >Thanks for starting to do this. I do architect databases and for
> >edacore I would work hard to avoid an N:N table. They aren't great.
> >It's better to have explicit FKs between tables. I might have a
> >single table which includes columns for all types of objects, and I
> >would have a group table with a FK parent field refering to itself.
> 
> But then you'd have to add/alter columns if you want to accomodate
> new object types.
> What's so bad about an N:N table?
> -- 
> Stephen.

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