PIW Relationships Modelling
Marco Stahl
marco.stahl at gmx.net
Sun Jul 17 16:04:08 EDT 2005
> Von: Chad Knepp <pyg at galatea.org>
> > Something like
> >
> > entity | output
> > ----------------------
> > Leguminosae nitrogen
> > animal shit
> >
> > would simplefy the adding of new plants(and other entitys), creating
> > patterns for groups of plants(and other entitys), adding/changing
> > properties/patterns for whole plant(entity)groups.
>
> My proposal attempts to solve this with the use of sets. Example:
>
> entity | output
> --------------------------------------
> set(all Leguminosae) nitrogen fixing
Maybe I'm wrong, but I thought in MySQL:
"A SET datatype can hold any number of strings from a PREDEFINED list of
strings specified during table creation."
That doesn't sounds like "easy updating" or adding user contributed
rules,plants :-)
> Ok, I'm still not sure about why this is important but I see it at
> best as being 5-6 levels of hierarchy which will not affect
> performance. Something like:
>
> entity | parent
> ---------------
> creature NULL
> animal creature
> plant creature
> leguminosae plant
> soya leguminosae
> max soya
> 'Chiffumy' max
>
> The real problem with this is that entity will not be unique which
> requires you to know a little more about the entity than just the top
> level.
Sorry i don't understand, "not unique"???
In my example tables I use the names just because of readability.
Every entity should have a unique numeric ID ('Chiffumy'=143423425).
Saludos, Marco
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