rdf_journal

Documentation
- Reference manual
- Packages
  - SWI-Prolog Semantic Web Library 3.0
    - Plugin modules for rdf_db
      - library(semweb/rdf_persistency): Providing persistent storage
        
        Enriching the journals
        
        rdf_journal_file/2
        
        rdf_db_to_file/2

Availability::- use_module(library(semweb/rdf_persistency)).

rdf_journal_file(?DB, ?JournalFile)

True if File is the absolute file name of an existing named graph DB. A journal file contains a sequence of Prolog terms of the following format.^{4Future versions
of this library may use an XML based language neutral format.}

start(Attributes): Journal has been opened. Currently Attributes contains a term time(Stamp).
end(Attributes): Journal was closed. Currently Attributes contains a term time(Stamp).
assert(Subject, Predicate, Object): A triple {Subject, Predicate, Object} was added to the database.
assert(Subject, Predicate, Object, Line): A triple {Subject, Predicate, Object} was added to the database with given Line context.
retract(Subject, Predicate, Object): A triple {Subject, Predicate, Object} was deleted from the database. Note that an rdf_retractall/3 call can retract multiple triples. Each of them have a record in the journal. This allows for‘undo’.
retract(Subject, Predicate, Object, Line): Same as above, for a triple with associated line info.
update(Subject, Predicate, Object, Action): See rdf_update/4.
begin(Id, Nest, Time, Message): Added before the changes in each database affected by a transaction with transaction identifier log(Message). Id is an integer counting the logged transactions to this database. Numbers are increasing and designed for binary search within the journal file. Nest is the nesting level, where‘0’is a toplevel transaction. Time is a time-stamp, currently using float notation with two fractional digits. Message is the term provided by the user as argument of the log(Message) transaction.
end(Id, Nest, Others): Added after the changes in each database affected by a transaction with transaction identifier log(Message). Id and Nest match the begin-term. Others gives a list of other databases affected by this transaction and the Id of these records. The terms in this list have the format DB:Id.