Provided by: libur-perl_0.470+ds-1_all bug


       UR::Object::Ghost - Abstract class for representing deleted objects not yet committed


         my $obj = Some::Class->get(1234);

         $obj->delete();   # $obj is now a UR::DeletedRef

         $ghost = Some::Class::Ghost->get(1234);
         $ghost->some_method;  # Works


       Ghost objects are a bookkeeping entity for tracking objects which have been loaded from an
       external data source, deleted within the application, and not yet committed.  This implies
       that they still exist in the external data source.  When the Context is committed, the
       existence of Ghost objects triggers commands to the external data sources to also delete
       the object(s).  When objects are brought into the Context by querying a data source, they
       are compared against any ghosts that may already exist, and matching objects are not re-
       loaded or returned to the user from a call to get().  If the user wants to get Ghost
       objects, they must call get() explicitly on the Ghost class.

       Each class in the system also has an associated Ghost class, the name of which is formed
       by tacking '::Ghost' to the name of the regular class.  Ghost classes do not have ghosts

       Instances of Ghosts are not instantiated with create() directly, they are created as a
       concequence of deleting a regular object instance.  A Ghost can be turned back into a
       "live" object by re-creating it, or rolling back the transaction it was deleted in.


       Applications will not, and should not, normally interact with Ghosts.  The whole Ghost
       system is scheduled for elimination as we refactor the Context and software transaction


       UR::Object, UR::Object::Type