Re: Lucid statement of the MV vs RM position?

There doesn't seem to be a formal model anywhere. Integrity constraints are not enforced at the database level.

http://www.pickwiki.com/cgi-bin/wiki.pl?PickDataStructure gives my description of the data structure, which is the point of difference in Pick. To quote - "one can see how the layout somewhat resembles that used in most SQL DBMS's". There is a brief comparison with objects and XML too. Pick 'sort-of' looks like everything, but is unique - and very useful.

http://www.pickwiki.com/cgi-bin/wiki.pl?PhilosophyOfPick gives my views of the philosophy behind Pick. I think even Bob would agree with this quote - "In the Multi-Value model there is no DBMS as such."

The above are informal descriptions - I certainly don't have any pretensions to ability at higher mathematics. C.D.T. certainly is the place for someone to raise this issue, and the lack of a formal definition is frustrating. But I'm not sure that Pick IS the right thing to have a formal description. It seems to me that there is something missing, in that it does not enforce constraints. In my view, one uses Pick to build an application which is, itself, the DBMS.

There is a mindset about the Relational Model that is disturbing. The point of view that says that there is no TRULY Relational DBMS because of incompetance or wickedness on the part of the SQL DBMS providers is just outright wrong. The problem is that it is difficult in the extreme to build a data store of whatever size desired, that can have some arbitrarily huge number of people changing the data in it, and that will provide the answer to any conceivable query - as if the data store were to be frozen until the query is done. Every time you put an index in, or some other cute little wrinkle to more cleverly do this, you are argueably de-normalising your database. Well, you are storing data in multiple places, anyway.

The idea of having a horrendously complex physical implementation - in order to provide the appearance of a clear logical model - is uncomfortable to me. I question, not the Relational Model, but whether implementing this aspect of it in this way is worth the trouble.

Were there any formal definitions of the Heirachical and Network Models? I was going to write "exempting the ones that Codd set up in order to show the RM was better", but then I realised that I haven't even seen these, and that maybe they would teach me something. Does anyone have a link to them? Received on Thu Apr 20 2006 - 23:41:30 CEST