Re: domain questionnaire

On Wed, 21 Feb 2001 02:06:42 GMT, vadim tropashko <vadim_member_at_newsranger.com> wrote:
>What is support for enumerable domains, besides database constraints?

I believe the ANSI standard for SQL specifies DOMAIN as a keyword. All I meant to say by enumerable, is that there should be some way to determine whether a given (atomic?) value is in the domain or not. However, you raise a good point below.

>Is equality all that database requires from domain? (Plus, maybe, '<'
>and more operations). Then, i assume that poorly defined object equality
>(through references, of course:-) should imply some undesirable consequences.

Of course, I attempted to cheat by saying "enumerable". It would likely be common to define a domain with ranges, which would best be implemented with relational operators other than equality. However, it might be acceptable to require them to be enumerable in principle.

The real point I wanted to make is that these are all issues which relate to sets of values in the representation, and not whatever might server to define domains in real-world objects.

Joshua Stern
JRStern_at_gte.net Received on Wed Feb 21 2001 - 04:56:01 CET