Re: the two questions

On Nov 27, 11:46 am, JOG <j..._at_cs.nott.ac.uk> wrote:

> Again, all in the real world, before we get to a database.

It seems to me that the discussion about the real world attributes is not precise and formal. Obviously it is enough to say that the identifier is the entity's attribute and that's that. Entity by definition is real world distinguishable thing. For example in my solution I defined that the identifier of the entity (or relationship) is the entity's attribute. You can see it on my web city. It is really simple.
My identifier also is identifier of the entity's (or relationship) abstraction.

Btw, can be many combinations and cases - databases with abstract entities (Donald Duck, Mickey Mouse, Pegasus...) All computers' games are not from real world, there are databases for future (an annual budget, for example), multimedia db, etc.

Vladimir Odrljin Received on Wed Nov 28 2007 - 16:09:29 CET