Contribute your views on what constitutes a good data model and why

Discussion Question 1: Defining the Database Model

The database Data Model is said to be the communication link between the designer, applications programmer, and user. Contribute your views on what constitutes a good data model and why.

Discussion Question 2: Keys and Relationships

A relational database is based on the fact that data in one table can be tied, or related to data in another table.  To do this, the database uses various types of keys to form or define these relationships.  The process of identifying, defining, and implementing these keys to enable data to be represented in the best way is one of the more important aspects of developing a well-defined database.  Discuss some of your thoughts on this area based on either your experience, readings in the book or other resources you can find.