Is it a prorperty or entity

Here's my elementary problem:

When modeling an entity E with properties P1, P2, ..., PN there is a proposition to divide E to E1, E2, ..., EM according to values of properties PX.

PX property domain consists of M values.

I do understand that modeling PX as property increases flexibility and functionality of the system.

I have allways tried to make the design as general as it could be without (sometimes even with) messing up domain constraints or ability to set up relationships, but at the end I allways had to resort to common sense logic and intutition (as opposed to NF rules and definitions).

Are rules here simply:
a) if meaning of other properties depend on a certain property (within problem specifications)
or
b) if meaning (or even type) of a relationship depends on a certain property (within ...)
then divide entity on this property?

Are there some resources that discuss this basic issue?

( GoranG79 AT hotmail.com ) Received on Fri Jun 14 2002 - 11:09:22 CEST