Hi Gus,
qRules contains support to update and roundtrip items from a SharePoint list and you could use BCS to map the list to a SQL table but there are limitations: for example, you have to set up BCS, the mapping is tightly coupled, etc.. In general, we recommend using Web Services to submit to SQL directly. Qdabra's DBXL Web Service has been widely adopted as a solution for that. It's cheap, has tons of features, and is the best (and only) solution out there today to map your existing InfoPath forms to SQL.
The Beginner edition is comparable to qRules in price - i.e. it's very inexpensive. Click on the Comparing Editions tab for more information and let us know if you'd like a demo.
Best!