Re: Mixing OO and DB

On Feb 7, 1:01 pm, topmind <topm..._at_technologist.com> wrote:
> Schema inheritance -- Most relational databases do not support schema
> inheritance. Although such a feature could be added in theory to
> reduce the conflict with OOP, relational proponents are less likely to
> believe in the utility of hierarchical taxonomies and sub-typing
> because they tend to view set-based taxonomies or classification
> systems as more powerful and flexible than trees. OO advocates point
> out that inheritance/subtyping models need not be limited to trees
> (though this is a limitation in many popular OO languages such as
> Java), but non-tree OO solutions are seen as more difficult to
> formulate than set-based variation-on-a-theme management techniques
> preferred by relational. At the least, they differ from techniques
> commonly used in relational algebra.

This snippet highlights a major problem with wikipedia articles which often combine two diametrically opposed views melded together. It would be much more educational to analyse both views separately.

First, the reference to a concrete programming language (such as Java) is amusing. It looks as silly as if relational proponent was searched for SQL artifacts in order to get some insight into relational theory.

Generally, taxonomies are brittle. In the earlier example of concepts matrix one have to decide whether to use an atribute such as "Has Tail" or negate it into "No Tail" -- the resulting taxonomies are quite different. The "No Tail" is considered more progressive, because with the "Has Tail" attribute Gorilla and Human no longer fit at the top of the evolutionary ladder! Received on Thu Feb 07 2008 - 23:34:41 CET