Hi Gary,
I've been working on getting FreeCEN's database of UK census data into a new search engine on and off for a few months now. Our goal is to create a search engine a la
http://freereg2.freereg.org.uk/ and our starting point is an existing system of VLD and DAT files which has been in use by the project for a couple of decades.
Models beginning with "freecen1_" are what we load the VLD and DAT files into -- our raw, un-transformed data.
Models beginning with "freecen_" are the working models we transform that raw data into, and what the search engine actually displays -- this should be of more interest to you.
The "search_record" and "place" models are what the search engine actually searches, and are pretty generic, so they can be common to FreeCEN and FreeREG.
I'd be happy to answer any questions about the data model or to point you to the code that actually uses it.
Ben