Re: Tree (forest) design

From: Neo <neo55592_at_hotmail.com>
Date: 8 Mar 2004 11:08:44 -0800
Message-ID: <4b45d3ad.0403081108.1972e241_at_posting.google.com>


> > > So you have a graph, not a tree. Why do you display it as a tree in your
> > > GUI? To confuse the user?
> >
> > Next you'll ask me, why do most databases show trees as tables :)
>
> Trees can be generalized into tables, but the reverse is not true.

The actual structure used to store the data, whether it be a table or tree can usually generate any view such as a table, tree or 4D. The actual storage structure optimizes a model for some views at the expense of being less efficient for others.

For example, RDM's internal data structure (aka relation) optimizes it for generating tabular views while making it less efficient at generating tree-like views.

Conversely, a model whose internal data strucuture uses trees optimizes it for generating tree views while making it less efficient at generating tabular views.

Try representing Ex076's data (normalized and NULL-less) and generating the report using RDM. It will be less efficient (roughly measured by execution time) than that of TDM/XDb1. Received on Mon Mar 08 2004 - 20:08:44 CET

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