Availability:built-in
recorded(?Key, 
?Value, ?Reference)True if Value is recorded under Key and has the 
given database Reference. If Reference is given, 
this predicate is semi-deterministic. Otherwise, it must be considered 
non-deterministic. If neither Reference nor Key is 
given, the triples are generated as in the code snippet below.92Note 
that, without a given Key, some implementations return 
triples in the order defined by recorda/2 
and recordz/2. 
See also current_key/1.
        current_key(Key),
        recorded(Key, Value, Reference)