Can Omega index a relational database?
Not directly - you need to write a script to dump the database into a form suitable for indexing with the "scriptindex" tool.
There is an example script to do this in the omega distribution: "dbi2omega". This is written in perl, using the perl DBI database interface. This will dump the database into a file: you will probably need to edit the script a bit to suit the layout of your database. You'll then need to write an index specification for scriptindex, and run scriptindex with the dumped data and your index specification (see the scriptindex documentation for details of how to do this).