If you are doing any work with FAST Search for SharePoint 2010 and need to index database content (e.g. SQL tables), as a general rule of thumb you should use BCS for this.

FS4SP does have a JDBC connector that is quite capable of indexing database content, though don’t just use this because you have FAST and think you need to.

The reason here is simple – you will have a much simpler migration experience to SharePoint 2013, as the JDBC connector is now no longer included.