vldm10 wrote:
> The databases with m:n relationships are the most complex. For some
> situation regarding m:n relationships, the relational database theory
> doesn't have appropriate solution.
> For example (in your solution) if employee A changes his name to ABC
> and after some period again changes his name from ABC to A (in a case
> of divorce) your solution doesn't work and PK-FK relationships is
> broken. The same thing if a department changes its name. It can happen
> that employee A works for the department 001 every second month, etc.
> Theoretically we can analyze the situations when all attributes of the
> particular entity (or relationship) change their values in the many
> (different or same) ways, times and combinations.
>
> Vladimir Odrljin
What situation doesn't have a solution in RM? I agree you can contrive
of examples that don't fit some given logical model. That's different
from saying "the relational database theory doesn't have appropriate
solution". Do you have an example?
--
David Portas
Received on Thu Feb 16 2006 - 11:45:36 CST
