phpman > perldoc > BSON::DBRef(3pm)

NAME
    BSON::DBRef - BSON type wrapper for MongoDB DBRefs

VERSION
    version v1.12.2

SYNOPSIS
        use BSON::Types ':all';

        my $dbref = bson_dbref( $oid, $collection_name );

DESCRIPTION
    This module provides a BSON type wrapper for MongoDB Database References
    <http://docs.mongodb.org/manual/reference/database-references/>.

    A DBRef is a special document format which references 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.)

    Use of DBRefs is discouraged, so this module is provided for backwards compatibility. "Manual
    references" <https://docs.mongodb.com/manual/reference/database-references/#document-references>
    are preferred when there is a need to reference other documents.

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

  ref
    Required. The name of 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.

    This may also be specified in the constructor as '$ref'.

  db
    Optional. 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.

    Not all other language drivers support the $db field, so using this field is not recommended.

    This may also be specified in the constructor as '$db'.

  extra
    Optional. A hash reference of additional fields in the DBRef document. Not all MongoDB drivers
    support this feature and you should not rely on it. This attribute exists solely to ensure
    DBRefs generated by drivers that do allow extra fields will round-trip correctly.

    USE OF THIS FIELD FOR NEW DBREFS IS NOT RECOMMENDED.

METHODS
  TO_JSON
    If the "BSON_EXTJSON" option is true, returns a hashref compatible with MongoDB's extended JSON
    <https://github.com/mongodb/specifications/blob/master/source/extended-json.rst> format, which
    represents it as a document as follows:

        { "$ref": "<collection name>", "$id": "<id>" }

    If the "BSON_EXTJSON" option is false, an error is thrown, as this value can't otherwise be
    represented in JSON.

AUTHORS
    *   David Golden <david AT mongodb.com>

    *   Stefan G. <minimalist AT lavabit.com>

COPYRIGHT AND LICENSE
    This software is Copyright (c) 2020 by Stefan G. and MongoDB, Inc.

    This is free software, licensed under:

      The Apache License, Version 2.0, January 2004