rdf_db:rdf_input_info(+Input,
-Modified, -Format)Gather information on Input. Modified is the last
modification time of the source as a POSIX time-stamp (see time_file/2).
Format is the RDF format of the file. See rdf_file_type/2
for details. It is allowed to leave the output variables unbound.
Ultimately the default modified time is‘0' and the format is
assumed to be
xml.