The first bit about the database only applies to SQLite DBs: an SQLite database will need to go in the "databases" directory and the name must match the connection string. The two I mentioned are two that I have seen used with Web2py.
I'm not sure what to make of that thread. It doesn't seem relevant. I presume you've read this: http://web2py.com/book/default/chapter/06?search=migrate#Legacy-Databases-and-Keyed-Tables The only other thing I was saying is that web2py is typically expecting there to be an auto-incrementing, primary key column named "id". It's possible you can get by without it. I'm just not sure. It is usually how a join is made.
