Re: no names allowed, we serve types only
Date: Mon, 15 Feb 2010 10:07:43 -0800 (PST)
On Feb 13, 12:53 pm, Keith H Duggar <dug..._at_alum.mit.edu> wrote:
> Of course the conventional definition of a relation's header
> is a set of ordered pairs of "attributes" of the form <A, T>
> where A is the "name" of the attribute (which must be unique
> within the header) and T is a type.
The more I study relational model, the less I appreciate the concept of type (domain). This is consistent with dbms vendors failed to deliver genuine rdbms extensibility via user defined types: when did you last time program a new type? It looks like the only important operation on any domain is equality, and the other ones are just predicates in disguise. Received on Mon Feb 15 2010 - 12:07:43 CST