XML Mapping
===========

The XML mapping driver enables you to provide the ODM metadata in
form of XML documents.

The XML driver is backed by an XML Schema document that describes
the structure of a mapping document. The most recent version of the
XML Schema document is available online at
`http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping.xsd <http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping.xsd>`_.
The most convenient way to work with XML mapping files is to use an
IDE/editor that can provide code-completion based on such an XML
Schema document. The following is an outline of a XML mapping
document with the proper xmlns/xsi setup for the latest code in
trunk.

.. code-block:: xml

    <doctrine-mongo-mapping xmlns="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping
                        http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping.xsd">
    
        ...
    
    </doctrine-mongo-mapping>

.. note::

    If you do not want to use latest XML Schema document please use link like
    `http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping-1.0.0-BETA12.xsd <http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping-1.0.0-BETA12.xsd>`_.
    You can change ``1.0.0-BETA12`` part of the URL to 
    `any other ODM version <https://github.com/doctrine/mongodb-odm/releases>`_.

The XML mapping document of a class is loaded on-demand the first
time it is requested and subsequently stored in the metadata cache.
In order to work, this requires certain conventions:


- 
   Each document/mapped superclass must get its own dedicated XML
   mapping document.
- 
   The name of the mapping document must consist of the fully
   qualified name of the class, where namespace separators are
   replaced by dots (.).
- 
   All mapping documents should get the extension ".dcm.xml" to
   identify it as a Doctrine mapping file. This is more of a
   convention and you are not forced to do this. You can change the
   file extension easily enough.

.. code-block:: php

    <?php

    $driver->setFileExtension('.xml');

It is recommended to put all XML mapping documents in a single
folder but you can spread the documents over several folders if you
want to. In order to tell the XmlDriver where to look for your
mapping documents, supply an array of paths as the first argument
of the constructor, like this:

.. code-block:: php

    <?php

    // $config instanceof Doctrine\ODM\MongoDB\Configuration
    $driver = new XmlDriver(array('/path/to/files'));
    $config->setMetadataDriverImpl($driver);

Simplified XML Driver
~~~~~~~~~~~~~~~~~~~~~

The Symfony project sponsored a driver that simplifies usage of the XML Driver.
The changes between the original driver are:

1. File Extension is .mongodb-odm.xml
2. Filenames are shortened, "MyProject\Documents\User" will become User.mongodb-odm.xml
3. You can add a global file and add multiple documents in this file.

Configuration of this client works a little bit different:

.. code-block:: php

    <?php
    $namespaces = array(
        'MyProject\Documents' => '/path/to/files1',
        'OtherProject\Documents' => '/path/to/files2'
    );
    $driver = new \Doctrine\ODM\MongoDB\Mapping\Driver\SimplifiedXmlDriver($namespaces);
    $driver->setGlobalBasename('global'); // global.mongodb-odm.xml

Example
-------

As a quick start, here is a small example document that makes use
of several common elements:

.. code-block:: xml

    // Documents.User.dcm.xml

    <?xml version="1.0" encoding="UTF-8"?>
    
    <doctrine-mongo-mapping xmlns="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping
                        http://doctrine-project.org/schemas/odm/doctrine-mongo-mapping.xsd">
    
        <document name="Documents\User" db="documents" collection="users">
            <field fieldName="id" id="true" />
            <field fieldName="username" name="login" type="string" />
            <field fieldName="email" type="string" unique="true" order="desc" />
            <field fieldName="createdAt" type="date" />
            <indexes>
                <index unique="true" dropDups="true">
                    <key name="username" order="desc">
                    <option name="safe" value="true" />
                </index>
            </indexes>
            <embed-one target-document="Documents\Address" field="address" />
            <reference-one target-document="Documents\Profile" field="profile">
                <cascade>
                    <all />
                </cascade>
            </reference-one>
            <embed-many target-document="Documents\Phonenumber" field="phonenumbers" />
            <reference-many target-document="Documents\Group" field="groups">
                <cascade>
                    <all />
                </cascade>
            </reference-many>
            <reference-one target-document="Documents\Account" field="account">
                <cascade>
                    <all />
                </cascade>
            </reference-one>
        </document>
    </doctrine-mongo-mapping>

Be aware that class-names specified in the XML files should be fully qualified.

.. note::

    ``field-name`` is the name of **property in your object** while ``name`` specifies
    name of the field **in the database**. Specifying latter is optional and defaults to
    ``field-name`` if not set explicitly.

Reference
---------

.. _xml_reference_lock:

Lock
^^^^

The field with the ``lock`` attribute will be used to store lock information for :ref:`pessimistic locking <transactions_and_concurrency_pessimistic_locking>`.
This is only compatible with the ``int`` field type, and cannot be combined with ``id="true"``.

.. code-block:: xml

    <doctrine-mongo-mapping>
        <field fieldName="lock" lock="true" type="int" />
    </doctrine-mongo-mapping>

.. _xml_reference_version:

Version
^^^^^^^

The field with the ``version`` attribute will be used to store version information for :ref:`optimistic locking <transactions_and_concurrency_optimistic_locking>`.
This is only compatible with ``int`` and ``date`` field types, and cannot be combined with ``id="true"``.

.. code-block:: xml

    <doctrine-mongo-mapping>
        <field fieldName="version" version="true" type="int" />
    </doctrine-mongo-mapping>

By default, Doctrine ODM updates :ref:`embed-many <embed_many>` and
:ref:`reference-many <reference_many>` collections in separate write operations,
which do not bump the document version. Users employing document versioning are
encouraged to use the :ref:`atomicSet <atomic_set>` or
:ref:`atomicSetArray <atomic_set_array>` strategies for such collections, which
will ensure that collections are updated in the same write operation as the
versioned parent document.