I am right now working on a project that has a database with over 100 tables in a database. Because of extreme time constraints the developers didn't build in any relationships or constraints between or in the tables. Now I need to remodel the database such that the database is more structured and normalized. I don't have much knowledge about the database design since it is a 2 year old application and the person who developed the database is now gone. I know remodelling the database would require knowledge of the existing database and business rules.
I was wondering if there are any tools that could suggest or discover relationships between tables. For eg. Lets say there are two tables named 'Customer' and 'Order'. I notice that there is a column named 'id' in Customer and a column named 'customer_id' in Order. So I ask the tool to discover a relationship between id and customer_id and it tells me that there is a one-one or one-many or no relationship by comparing values. I heard ERWin would be able to do that but thats expensive. Please do let me know asap.