Re: Foreign key problem
Date: Thu, 15 Jun 2006 16:25:19 +0300
> Maybe I should have said that the word glue is a time-waster without any
> practical use, one of those casual metaphors, so rife in IT, that end up
> taking on a life of their own. Some people think keys hold a database
> together, as for what holds a relation together (in a database), I'd say
> it is the complete definition of whatever theory, eg., relational theory
> we use. One could just as easily say that the defined operators are the
> glue, eg., JOIN.
Maybe. But Codd said this about domains. He said that by looking at the domains one can tell if the database can be partitioned in unrelated databases. I understand your position about the operators, but I think JOIN is not one of them (a part of the glue). It is defined on the relations, which are defined on the domains. Maybe Codd viewed operators as special kind of relations so they are included anyway somehow.
> Salesman stole my copy of RM/V2, no idea why. Out-of-print now, not to
> be found in any library I've searched.
Sorry, but I don't remember the page. I think I read about this "glue" last week. I would search it if you really want, but there are entire chapters dedicated to this matter from what I've read until now. Received on Thu Jun 15 2006 - 15:25:19 CEST