While strings, numbers, dates and XML entities are "native" SQL datatypes, RDF literal with non-default type or language have no exact matches among standard SQL types. Virtuoso introduces a special data type called "RDF_BOX" in order to handle that cases. Instance of RDF_BOX consists of data type, language, the content (or beginning characters of a long content) and a possible reference to DB.DBA.RDF_OBJ table if the object is too long to be held in-line in some table or should be outlined for free-text indexing.

Usually applications do not need to access internals of an RDF boxes. This datatype is used in system tables but almost all SPARQL and RDF operations use standard SQL datatypes for arguments and return values.