Re: Data Redundancy

Your solution is good. This solution is not specific just for the RM. It is above the RM level. It is on the Conceptual Level and it is very important. That means that you can implement your solution in file system with some procedural language. However you must build some rutines which exist in the database's software.

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 Received on Thu Feb 16 2006 - 02:39:08 CST