Lock Protection
===============

Lock protection will prevent data corruption when multiple users edit an object at the same time.

Example
-------

1) Alice starts to edit the object
2) Bob starts to edit the object
3) Alice submits the form
4) Bob submits the form

In this case, a message will tell Bob that someone else has edited the object,
and that he must reload the page and apply the changes again.

Enable Lock Protection
----------------------

By default, lock protection is disabled.
You can enable it in your ``sonata_admin`` configuration:

.. code-block:: yaml

    # config/packages/sonata_admin.yaml

    sonata_admin:
        options:
            lock_protection: true

You must also configure each entity that you want to support by adding a
field called ``$version`` on which the Doctrine ``Version`` feature is activated.

Using Attributes::

    // src/Entity/Car.php

    namespace App\Entity;

    use Doctrine\DBAL\Types\Types;
    use Doctrine\ORM\Mapping as ORM;

    class Car
    {
        // ...

        #[ORM\Column(type: Types::INTEGER)]
        #[ORM\Version]
        private ?int $version = null;

        // ...
    }

Using XML:

.. code-block:: xml

    <?xml version="1.0" encoding="UTF-8"?>
    <!-- src/Resources/orm/Car.orm.xml -->
    <doctrine-mapping>
        <entity name="App\Entity\Car">
            <!-- ... -->

            <field name="version" type="integer" version="true"/>

            <!-- ... -->
        </entity>
    </doctrine-mapping>

For more information about this visit the `Doctrine docs <https://www.doctrine-project.org/projects/doctrine-orm/en/latest/reference/transactions-and-concurrency.html#optimistic-locking>`_

.. note::

    If the object model manager does not support object locking,
    the lock protection will not be triggered for the object.
    Currently, only the ``SonataDoctrineORMAdminBundle`` supports it.