Re: TRM - Morbidity has set in, or not?

Bob Badour wrote:
> Actually, the point you are asking about above is more
> about expression bias than access paths. Network and
> hierarchic data models limit both by combining separate
> concerns.
[snip much more]

Fascinating fascinating. Your response was enlightening, it really helped to clarify the issues for me. And this vocabulary of "expression bias" is also clarifying. I realize I have a lot of reading on fundamentals to do and I'm working on getting Date's AITDS; but, aside from that can you recommend any material that specifically addresses issues concerning expression bias and access paths?

> The problem I perceived that you expressed above amounts
> to: How the hell am I going to write that analytic
> program in the first place?!?
>
> Because the concern for performance is mixed with the
> oncern for correctness in network data models, one often
> finds that--after the performance needs of one requirement
> are met--it is extremely difficult to express anything
> else one wants. Even after creating such a program, one
> will encounter the same performance issues. If you have to
> change the access paths for the other analysis, you are
> pretty much screwed.

Yes that's exactly the problem I was trying to communicate. I thought perhaps a relational perspective would help me to better design such programs. In the past such problems have irked me greatly. Are these design issues inherently hard?

Bob Badour wrote:
> Keith H Duggar wrote:
> > What about APL, Joy, K, and Prolog for example? What
> > are their good and bad points from a relational support
> > perspective?
>
> They are all first and foremost programming languages,
> which makes them orthogonal to the RM ... In a sense,
> "RM programming language" is an oxymoron.

I admit I'm having trouble grasping this concept. I can see that various languages can be paired with various data models. However, doesn't a programming language need some glue, some contructs to support a particular data model? For example in your code example you had keywords such as FROM WHERE JOIN that seem semantically tied to the relational model and yet they are part of the language proper.

Thank you again, very helpful.

• Keith ---