SWI-Prolog -- Modifying the RDF store

[det]rdf_assert(+S, +P, +O)
[det]rdf_assert(+S, +P, +O, +G): Assert a new triple. If O is a literal, certain Prolog terms are translated to typed RDF literals. These conversions are described with rdf_canonical_literal/2.
If a type is provided using Value^^Type syntax, additional conversions are performed. All types accept either an atom or Prolog string holding a valid RDF lexical value for the type and xsd:float and xsd:double accept a Prolog integer.
[nondet]rdf_retractall(?S, ?P, ?O)
[nondet]rdf_retractall(?S, ?P, ?O, ?G): Remove all matching triples from the database. Matching is performed using the same rules as rdf/3. The call does not instantiate any of its arguments.
rdf_create_bnode(--BNode): Create a new BNode. A blank node is an atom starting with _:. Blank nodes generated by this predicate are of the form _:genid followed by a unique integer.