Re: Domains, types, and application engineering ....

Dan wrote:
> Do domains in predicate calculus have behavior?

 Insightful question. And the answer is 'no'. A domain's behavior is governed by the relations in which it plays a part.

 There's a case for a kind of 'functional' relational-DBMS where domains have no operators at all. Instead the domain's 'behavior' is expressed with a collection of relation definitions.

> I believe asking
> questions and reasoning about properites of things and relationships
> predates behavior "in databases or DBMSs" by several centuries, no?

  Oh yes.

 [ snip ]

> So maybe the question
> could be redirected as to what "ought" to be the behavior of domains
> mentioned on a piece of paper be? Should they dance? Back-flips?

   If you can describe what a 'back-flip' is on a piece of paper, you can model it.

> A tune would be nice.

   Glad you asked!

   *ahem*

   "I am the very model of an application developer,

      I know 'bout databases, both SQL-Server and Oracular,
        I can whip you up a GUI with speed that's quite spectacular,
     and I know the ins and outs of every pretty-picture data modeller!"