When I started here the first thing I did was model the DB, as one did not exist. Fortunately we have Visio 2007, and I was able to reverse engineer the DB. That atleast got the tables and views for me. And it made our auditors happy when they came thru.

ERWin is probably the class of the field, but it can be expensive.

Regarding development process, it's a coin flip. A small shop can get away with creating the objects as you go. but once more than 3 people have to develop in the DB, a model is worth its weight in gold. Easy reference when writing queries because your relationships are visible. And when new objects are created it allows the entire team to know what to expect. My preference? Model 1st.

Just my .02 worth. 😀