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	Tue, 25 Aug 2015 02:09:16 -0700 (PDT)
Date:	Tue, 25 Aug 2015 11:09:15 +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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References:	<20150824223846 DOT 0ba61ba7 AT jive DOT levalinux DOT org>
	<20150825022302 DOT 21819 DOT qmail AT stuge DOT se>
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If you by redundancy more than one link have to change if something is changed for example a link in two directions I think you are correct and redundancy should be avoided. If a search in opposite direction of link is needed it could be done then needed but it may of course be to time consuming.





On Tue, 25 Aug 2015 10:24:41 +0200
"Levente (leventelist AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com> wrote:

> Thanks for the comment. I don't really see how can we can implement the
> that any to any object attachments with FKs. Can you make an example?
> 
> I'll make the names shorter.
> 
> On Tue, Aug 25, 2015 at 4:23 AM, Peter Stuge (peter AT stuge DOT se) [via
> geda-user AT delorie DOT com] <geda-user AT delorie DOT com> wrote:
> 
> > Hi,
> >
> > Lev (leventelist AT gmail DOT com) [via geda-user AT delorie DOT com] wrote:
> > > Here I propose the file format of the next generation of PCB.
> > ..
> > > Okay. I'm not a database architect, and you can now start throwing
> >
> > 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.
> >
> > Please eliminate all the redundancy in your schema. pcb_object -> pcb
> > pcb_id -> id and so on. Otherwise queries become immensely verbose.
> > It looks like it is important to qualify every column, but actually
> > in queries if there is any ambiguity then columns can optionally be
> > qualified with the table name, and if there isn't any then the
> > redundancy is avoided. This is a matter of style, but I think an
> > important one for efficiency and both readability and writability of
> > queries down the line.
> >
> >
> > > I know that sqlite is yet another dependency
> >
> > It's fine, don't worry.
> >
> >
> > //Peter
> >

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