Re: Generic Modeling

Hi Brian,

In your original message (below), you have four bulleted requests. The fact that you have to ask the fourth request should be persuasive enough that the entire idea was bad from its inception.

A relational dbms is already the most powerful generic logic system available for machine interpretable semantic modelling. To do its job properly, it needs to work with the valid logical schema that most closely resembles the conceptual schema. Unless your conceptual schema has a single entity, "thing", the one table approach does not resemble the conceptual schema in any way, shape or form. Likewise for the two table approach.

A relation (or table) establishes an n-ary relationship among data. The progression from one table to two tables already suggests the need to reinvent the dbms -- albeit poorly. The fourth point below confirms it.

The second and third points below presuppose the incorrect answer to the first, and as such require no response.

Regards,
Bob

"Brian Smith" <brian-l-smith_at_uiowa.edu> wrote in message news:60360d48.0112301941.2b44f613_at_posting.google.com...
> I am looking for information about generic modeling in relational
> databases (especially SQL). In particular, I have heard about the
> one-table-approach (the "thing" or "stuff" table), the two-table
> approach ("thing" and "relationship"), etc., etc. I have also seen a
> presentation on milder forms of generic database design (e.g.
> combining multiple code tables together, merging parts of CUSTOMER,
> EMPLOYEE, and COMPANY tables into a PARTY table, etc.
>
> In particular, I am looking for:
> * persuasive theoretical arguments about why generic modeling in the
> "thing-relationship" sense is good or bad for database design.
> * objective performance measurements and
> performance-enhancing techniques for the generic approach
> (preferable that are at least applicable to Oracle
> or PostgreSQL).
> * Storing various levels of meta-data (meta-meta-data, meta-data,
> and data)
> together in the same schema/table.
> * Ways to implement a relationl schema on top of a generic schema
> (or
> vice-versa); for example, creating (updatable) views on a "THING"
> relation
> to get back to "EMPLOYEE", "CUSTOMER", etc.
>
> Where can I find information about these specific topics? I am
> grateful to receive any pointers to resources you might know about. I
> tried searching on google but came up nearly empty; I guess I wasn't
> creative enough with my search criterea ("generic modeling SQL" is
> too, well, generic).
>
> Thanks,
> Brian
Received on Mon Dec 31 2001 - 22:11:02 CET