[lug] Data source modeling tool recommendation

[rise]

One of my current projects involves centralizing and rationalizing a set
of legacy data sources.  I'm looking for an open-source tool to help me
model what I've got (from servers down to the level of common keys) and
what I want.  The latter most database modeling tools will do fine, but
the former seems to overlap with ER diagram tools, network management
software, db modelers, workflow tools, etc.  Any favorite tools?  Ideally
I want something that makes it easier to grasp the system as a whole and
start the process of reducing it to a more normalized form.

-- 
Jonathan Conway						      rise at knavery.net
history is paling & my surge protection failed, & so I FRIED
						- Concrete Blonde, "Fried"