Vincent Michel <vincent.michel@logilab.fr> [Tue, 23 Apr 2013 14:13:58 +0200] rev 8944
[sql] preprocess_entity uses lgdb helper's SQL converters.
The preprocess_entity does not yield anymore the conversion logic for different
base types, but relies on a new SQL_CONVERTERS dictionary of the db helper.
This will allow later inclusion of new base types.