def get_dtypes_db(self, entity_uri):
""" returns an entity data type """
# haven't found it yet, so look in database
lequiv = LinkEquivalence()
lequiv.predicates = self.predicates
dtypes = lequiv.get_data_types_from_object(entity_uri)
self.predicates = lequiv.predicates
self.entity_dtypes[entity_uri] = dtypes
return dtypes
