This class is a wrapper around the NamedFieldCmp<>, allowing you to sort a vector (or other container) of DBData objects.
This class will parse each record before passing the result on to NamedFieldCmp<> and returning the result. All the parsing work is then thrown away, so this is more of a convenience class than for performance.
This class expects that all the DBData given to it is one of the known records which have a parser. If the record unrecognized, it will throw a std::logic_error exception.