Re: Something new for the New Year (2008).
Date: Thu, 17 Jan 2008 10:23:15 -0800 (PST)
On Jan 15, 7:03 pm, Gene Wirchenko <ge..._at_ocis.net> wrote:
> Rob <rmpsf..._at_gmail.com> wrote:
> >You are 100% correct. I totally agree, the model I proposed would not
> >stand up. I said essentially the same thing in
> >(and was called to task for saying that 'there is no "clean,
> >efficient way to store this information" in the relational
> >model that satisfies all constraints').
> No wonder. For example, the deficiency of an SQL DBMS does not
> speak against the RM.
> Gene Wirchenko
Again, I agree 100%. The SQL paradigm is a horror, and the implementations of SQL DBMSs encourage practices that are not just bad, they are dangerous. Personally, I believe that the SQL paradigm is the single biggest obstacle to wider use of relational databases.
I believe that from your perspective, an SQL DBMS is a necessary evil: The only available engine that allows you to map your RM model abstractions to operational relational DBs. Not dissimilarly, I see an SQL DBMS as a component. However, because the A-L representation can replace both the PKFK and JT representations, it makes it possible to derive a simpler, relationship-oriented data model at the same level of abstraction as SQL. My objective is a graphical data model defined at a higher level of abstraction that makes relationship joins transparent and therefore usable by less-trained knowledge workers. This will be described in the "next installment" of my website.
I refer you to Codd's 1980 paper, "DATA MODELS IN DATABASE MANAGEMENT" in which he wrote:
A data model may be used in any of the following: 1) as a tool for specifying the kinds of data and data organization that are permissable in a specific database; 2) as a basis for developing a general design methodology for databases;
3) as a basis for coping with evolution of databases so as to have minimal logical impact on existing applications programs and terminal activities;
4) as a basis for the development of families of very high level languages for query and data manipulation; 5) as a focus for DBMS architecture;
6) as a vehicle for research into the behavioral properties of alternative organizations of data.
I see this work on A-L as relating directly to items 4-6.
I thank you for your insightful comments. I think it's time we wrapped up this thread and moved on.
See "Data Models and Levels of Abstraction".
Rob Received on Thu Jan 17 2008 - 19:23:15 CET