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referenced_record(+DBRef, -Value)

Succeeds if Value is the Term recorded under the database reference DBRef.
DBRef
A database reference.
Value
Any Prolog term.

Description

The database reference DBRef must refer to a term that has previously been recorded in the indexed database. Database references can be obtained from the predicates recorda/3, recordz/3 and recorded/3. Value is unified with a copy of the recorded term. Note that this is the case even if the original database entry has been removed since the database reference was obtained (logical update semantics).

Modes and Determinism

Exceptions

(4) instantiation fault
DBRef is not instantiated.
(5) type error
DBRef is neither a variable nor a database reference.

Examples

   [eclipse]: recordz(beer, paulaner, Ref), referenced_record(Ref, X).
   Ref = 'DBREF'(16'50470d00)
   X = paulaner
   yes.

   [eclipse]: recorded(beer, _, Ref), referenced_record(Ref, X).
   Ref = 'DBREF'(16'50470d00)
   X = paulaner     More? (;)
   yes.

   [eclipse]: recorded(beer, _, Ref), erase(Ref), referenced_record(Ref, X).
   Ref = 'DBREF'(16'50470d00)
   X = paulaner     More? (;)
   yes.

Error:
   referenced_record(_, Value).         (Error 4)
   referenced_record(123, Value).       (Error 5)



See Also

recorda / 3, recordz / 3, recorded / 3, erase / 1, referenced_record / 2