I am focusing on a sizable SQL Server database without any documentation. It is possible to good, ideally free, documentation generator tool I'm able to use to obtain my mind around it.
One tool that I am using increasingly more to get this done kind of factor is LinqPad (www.linqpad.internet). This is much more than simply a Linq tool. It's very proficient at permitting you to definitely drill lower through table associations, as lengthy as FK's are correctly in position. It is free of charge.
Around the non-free side, we use Red-colored-Gates SQL Doc (http://www.red-colored-gate.com/items/sql-development/sql-doc/). Excellent tool.