I understand (and its straightforward) when you want to create a index for something simple like Products.
But how do you go about creating a Solr index when you have data coming from 10-15 database tables, and the tables have unrelated data? The issue is then you would have many 'columns' in your index, and they will be NULL for much of the data since you are trying to shove 15 db tables into a single Solr/Lucense index. This must be a common problem, what are the potential solutions?
