perldoc > BSON::DBRef

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📛 NAME

BSON::DBRef — BSON type wrapper for MongoDB DBRefs

🚀 Quick Reference

Use Case	Command	Description
📦 Creating a DBRef	bson_dbref( $oid, $collection_name )	Import from BSON::Types and create a DBRef object.
🔑 Access referenced document ID	$dbref->id	Returns the _id value (typically a BSON::OID).
📁 Get collection name	$dbref->ref	Returns the collection name as a string.
🗄️ Get database name	$dbref->db	Returns the optional database name (undef if not set).
📤 Export to MongoDB Extended JSON	$dbref->TO_JSON (with $BSON::BSON_EXTJSON = 1)	Returns a hashref like { '$ref' => …, '$id' => … }.

🏷️ 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

📛 NAME 🚀 Quick Reference 🏷️ VERSION 📝 SYNOPSIS 📖 DESCRIPTION 🧩 ATTRIBUTES 🔧 METHODS 👥 AUTHORS ©️ COPYRIGHT AND LICENSE