Re: Data Display & Modeling

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"Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message news:c7e3hr$t0c$1_at_news.netins.net...

> 4. Now figure that relational theory is not related to the physical
storage
> of the data.
>
> Then there is no reason to even add the notations to switch between the
> di-graph and relational provided that everything the system needs to store
> the data is provided in the di-graph "picture" -- there just needs to be a
> mapping between the di-graph and the physical model, which can be
optimized
> for machine processes (therfore, likely NOT relational!)

Chaces are you'll need more than a di-graph. At least one di-graph for each VIEW.
For translating among those di-graphs, you'll need another one. The hard part isn't the mapping from one di-graph to the physical model, but from one di-graph to N other di-graphs. Soon you'll begin to work with mappings of paths in di-graphs. Then you'll need some kind of "normalization" theory. You'll end up with something resembling relational model.

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