NAME

       MongoDB::DBRef - Native DBRef support

VERSION

       version 0.702.1

SYNOPSIS

           my $dbref = MongoDB::DBRef->new( db => 'my_db', ref => 'my_collection', id => 123 );
           $coll->insert( { foo => 'bar', other_doc => $dbref } );

           my $other_doc = $coll->find_one( { foo => 'bar' } )->{other_doc}->fetch;

DESCRIPTION

       This module provides support for database references (DBRefs) in the Perl MongoDB driver.
       A DBRef is a special embedded document which points to another document in the database.
       DBRefs are not the same as foreign keys and do not provide any referential integrity or
       constraint checking. For example, a DBRef may point to a document that no longer exists
       (or never existed.)

NAME

       MongoDB::DBRef - A MongoDB database reference

ATTRIBUTES

   db
       Required. The database in which the referenced document lives. Either a MongoDB::Database
       object or a string containing the database name. The object will be coerced to string
       form.

   ref
       Required. The collection in which the referenced document lives. Either a
       MongoDB::Collection object or a string containing the collection name. The object will be
       coerced to string form.

   id
       Required. The "_id" value of the referenced document. If the "_id" is an ObjectID, then
       you must use a MongoDB::OID object.

   client
       Optional. A MongoDB::MongoClient object to be used to fetch the referenced document from
       the database. You must supply this attribute if you want to use the "fetch" method.

       When you retrieve a document from MongoDB, any DBRefs will automatically be inflated into
       "MongoDB::DBRef" objects with the "client" attribute automatically populated.

       It is not necessary to specify a "client" if you are just making DBRefs to insert in the
       database as part of a larger document.

   verify_db
       Optional. Check that the referenced database exists before trying to fetch a document from
       it. The default is 1. Set to 0 to disable checking.

   verify_coll
       Optional. Check that the referenced collection exists before trying to fetch a document
       from it. The default is 1. Set to 0 to disable checking.

METHODS

   fetch
       Retrieve the referenced document from the database. If the document does not exist, you'll
       get back "undef". You must populate the "client" attribute of the DBRef object in order to
       use this method. If there's no "client", "fetch" will throw a fatal error.

       If "verify_db" or <verify_coll> are on, "fetch" will throw a fatal error if the database
       or collection concerned does not exist.

AUTHORS

       •   Florian Ragwitz <rafl@debian.org>

       •   Kristina Chodorow <kristina@mongodb.org>

       •   Mike Friedman <mike.friedman@10gen.com>

COPYRIGHT AND LICENSE

       This software is Copyright (c) 2013 by 10gen, Inc..

       This is free software, licensed under:

         The Apache License, Version 2.0, January 2004