database diagrams

At one time or another we have all been handed a new system and its related database(s). How do you wrap your arms around the entities and grasp the main concepts. For me, nothing beats an ERD and although Erwin and Microsoft Visio do good jobs at presenting these, the best product I've worked with for reverse-engineering a database is SchemaSpy. And it's free! As in beer. Check it out the next time you need a diagram. (I have no relationship with the author of SchemaSpy; I just think the product is really cool and wish I could write Java like this.

http://schemaspy.sourceforge.net/