Merge 4.2 into 4.3 (#2800)

docs/eloquent-models/model-class.txt

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+.. _laravel-eloquent-model-class:
+
+====================
+Eloquent Model Class
+====================
+
+.. facet::
+   :name: genre
+   :values: reference
+
+.. meta::
+   :keywords: php framework, odm, code example, authentication, laravel
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 2
+   :class: singlecol
+
+Overview
+--------
+
+This guide shows you how to use the {+odm-long+} to define and
+customize Laravel Eloquent models. You can use these models to work with
+MongoDB data by using the Laravel Eloquent object-relational mapper (ORM).
+
+The following sections explain how to add Laravel Eloquent ORM behaviors
+to {+odm-short+} models:
+
+- :ref:`laravel-model-define` demonstrates how to create a model class.
+- :ref:`laravel-authenticatable-model` shows how to set MongoDB as the
+  authentication user provider.
+- :ref:`laravel-model-customize` explains several model class customizations.
+- :ref:`laravel-model-pruning` shows how to periodically remove models that
+  you no longer need.
+
+.. _laravel-model-define:
+
+Define an Eloquent Model Class
+------------------------------
+
+Eloquent models are classes that represent your data. They include methods
+that perform database operations such as inserts, updates, and deletes.
+
+To declare a {+odm-short+} model, create a class in the ``app/Models``
+directory of your Laravel application that extends
+``MongoDB\Laravel\Eloquent\Model`` as shown in the following code example:
+
+.. literalinclude:: /includes/eloquent-models/Planet.php
+   :language: php
+   :emphasize-lines: 3,5,7
+   :dedent:
+
+By default, the model uses the MongoDB database name set in your Laravel
+application's ``config/database.php`` setting and the snake case plural
+form of your model class name for the collection.
+
+This model is stored in the ``planets`` MongoDB collection.
+
+.. tip::
+
+   Alternatively, use the ``artisan`` console to generate the model class and
+   change the ``Illuminate\Database\Eloquent\Model`` import to ``MongoDB\Laravel\Eloquent\Model``.
+   To learn more about the ``artisan`` console, see `Artisan Console <https://laravel.com/docs/{+laravel-docs-version+}/artisan>`__
+   in the Laravel docs.
+
+To learn how to specify the database name that your Laravel application uses,
+:ref:`laravel-quick-start-connect-to-mongodb`.
+
+
+.. _laravel-authenticatable-model:
+
+Extend the Authenticatable Model
+--------------------------------
+
+To configure MongoDB as the Laravel user provider, you can extend the
+{+odm-short+} ``MongoDB\Laravel\Auth\User`` class. The following code example
+shows how to extend this class:
+
+.. literalinclude:: /includes/eloquent-models/AuthenticatableUser.php
+   :language: php
+   :emphasize-lines: 3,5,7
+   :dedent:
+
+To learn more about customizing a Laravel authentication user provider,
+see `Adding Custom User Providers <https://laravel.com/docs/{+laravel-docs-version+}/authentication#adding-custom-user-providers>`__
+in the Laravel docs.
+
+.. _laravel-model-customize:
+
+Customize an Eloquent Model Class
+---------------------------------
+
+This section shows how to perform the following Eloquent model behavior
+customizations:
+
+- :ref:`laravel-model-customize-collection-name`
+- :ref:`laravel-model-customize-primary-key`
+- :ref:`laravel-model-soft-delete`
+- :ref:`laravel-model-cast-data-types`
+- :ref:`laravel-model-mass-assignment`
+
+.. _laravel-model-customize-collection-name:
+
+Change the Model Collection Name
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+By default, the model uses the snake case plural form of your model
+class name. To change the name of the collection the model uses to retrieve
+and save data in MongoDB, override the ``$collection`` property of the model
+class.
+
+.. note::
+
+   We recommend using the default collection naming behavior to keep
+   the associations between models and collections straightforward.
+
+The following example specifies the custom MongoDB collection name,
+``celestial_body``, for the ``Planet`` class:
+
+.. literalinclude:: /includes/eloquent-models/PlanetCollection.php
+   :language: php
+   :emphasize-lines: 9
+   :dedent:
+
+Without overriding the ``$collection`` property, this model maps to the
+``planets`` collection. With the overridden property, the example class stores
+the model in the ``celestial_body`` collection.
+
+.. _laravel-model-customize-primary-key:
+
+Change the Primary Key Field
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To customize the model's primary key field that uniquely identifies a MongoDB
+document, override the ``$primaryKey`` property of the model class.
+
+By default, the model uses the PHP MongoDB driver to generate unique ObjectIDs
+for each document your Laravel application inserts.
+
+The following example specifies the ``name`` field as the primary key for
+the ``Planet`` class:
+
+.. literalinclude:: /includes/eloquent-models/PlanetPrimaryKey.php
+   :language: php
+   :emphasize-lines: 9
+   :dedent:
+
+To learn more about primary key behavior and customization options, see
+`Eloquent Primary Keys <https://laravel.com/docs/{+laravel-docs-version+}/eloquent#primary-keys>`__
+in the Laravel docs.
+
+To learn more about the ``_id`` field, ObjectIDs, and the MongoDB document
+structure, see :manual:`Documents </core/document>` in the MongoDB server docs.
+
+.. _laravel-model-soft-delete:
+
+Enable Soft Deletes
+~~~~~~~~~~~~~~~~~~~
+
+Eloquent includes a soft delete feature that changes the behavior of the
+``delete()`` method on a model. When soft delete is enabled on a model, the
+``delete()`` method marks a document as deleted instead of removing it from the
+database. It sets a timestamp on the ``deleted_at`` field to exclude it from
+retrieve operations automatically.
+
+To enable soft deletes on a class, add the ``MongoDB\Laravel\Eloquent\SoftDeletes``
+trait as shown in the following code example:
+
+.. literalinclude:: /includes/eloquent-models/PlanetSoftDelete.php
+   :language: php
+   :emphasize-lines: 6,10
+   :dedent:
+
+To learn about methods you can perform on models with soft deletes enabled, see
+`Eloquent Soft Deleting <https://laravel.com/docs/{+laravel-docs-version+}/eloquent#soft-deleting>`__
+in the Laravel docs.
+
+.. _laravel-model-cast-data-types:
+
+Cast Data Types
+---------------
+
+Eloquent lets you convert model attribute data types before storing or
+retrieving data by using a casting helper. This helper is a convenient
+alternative to defining equivalent accessor and mutator methods on your model.
+
+In the following example, the casting helper converts the ``discovery_dt``
+model attribute, stored in MongoDB as a `MongoDB\\BSON\\UTCDateTime <https://www.php.net/manual/en/class.mongodb-bson-utcdatetime.php>`__
+type, to the Laravel ``datetime`` type.
+
+.. literalinclude:: /includes/eloquent-models/PlanetDate.php
+   :language: php
+   :emphasize-lines: 9-11
+   :dedent:
+
+This conversion lets you use the PHP `DateTime <https://www.php.net/manual/en/class.datetime.php>`__
+or the `Carbon class <https://carbon.nesbot.com/docs/>`__ to work with dates
+in this field. The following example shows a Laravel query that uses the
+casting helper on the model to query for planets with a ``discovery_dt`` of
+less than three years ago:
+
+.. code-block:: php
+
+   Planet::where( 'discovery_dt', '>', new DateTime('-3 years'))->get();
+
+To learn more about MongoDB's data types, see :manual:`BSON Types </reference/bson-types/>`
+in the MongoDB server docs.
+
+To learn more about the Laravel casting helper and supported types, see `Attribute Casting <https://laravel.com/docs/{+laravel-docs-version+}/eloquent-mutators#attribute-casting>`__
+in the Laravel docs.
+
+.. _laravel-model-mass-assignment:
+
+Customize Mass Assignment
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Eloquent lets you create several models and their attribute data by passing
+an array of data to the ``create()`` model method. This process of inserting
+multiple models is called mass assignment.
+
+Mass assignment can be an efficient way to create multiple models. However, it
+can expose an exploitable security vulnerability. The data in the fields
+might contain updates that lead to unauthorized permissions or access.
+
+Eloquent provides the following traits to protect your data from mass
+assignment vulnerabilities:
+
+- ``$fillable`` contains the fields that are writeable in a mass assignment
+- ``$guarded`` contains the fields that are ignored in a mass assignment
+
+.. important::
+
+   We recommend using ``$fillable`` instead of ``$guarded`` to protect against
+   vulnerabilities. To learn more about this recommendation, see the
+   `Security Release: Laravel 6.18.35, 7.24.0 <https://blog.laravel.com/security-release-laravel-61835-7240>`__
+   article on the Laravel site.
+
+In the following example, the model allows mass assignment of the fields
+by using the ``$fillable`` attribute:
+
+.. literalinclude:: /includes/eloquent-models/PlanetMassAssignment.php
+   :language: php
+   :emphasize-lines: 9-14
+   :dedent:
+
+The following code example shows mass assignment of the ``Planet`` model:
+
+.. code-block:: php
+
+   $planets = [
+       [ 'name' => 'Earth', gravity => 9.8, day_length => '24 hours' ],
+       [ 'name' => 'Mars', gravity => 3.7, day_length => '25 hours' ],
+   ];
+
+   Planet::create($planets);
+
+The models saved to the database contain only the ``name`` and ``gravity``
+fields since ``day_length`` is omitted from the ``$fillable`` attribute.
+
+To learn how to change the behavior when attempting to fill a field omitted
+from the ``$fillable`` array, see `Mass Assignment Exceptions <https://laravel.com/docs/{+laravel-docs-version+}/eloquent#mass-assignment-exceptions>`__
+in the Laravel docs.
+
+.. _laravel-model-pruning:
+
+Specify Pruning Behavior
+------------------------
+
+Eloquent lets you specify criteria to periodically delete model data that you
+no longer need. When you schedule or run the ``model:prune`` command,
+Laravel calls the ``prunable()`` method on all models that import the
+``Prunable`` and ``MassPrunable`` traits to match the models for deletion.
+
+To use this feature with models that use MongoDB as a database, add the
+appropriate import to your model:
+
+- ``MongoDB\Laravel\Eloquent\Prunable`` optionally performs a cleanup
+  step before deleting a model that matches the criteria
+- ``MongoDB\Laravel\Eloquent\MassPrunable`` deletes models that match the
+  criteria without fetching the model data
+
+.. note::
+
+   When enabling soft deletes on a mass prunable model, you must import the
+   following {+odm-short+} packages:
+
+   - ``MongoDB\Laravel\Eloquent\SoftDeletes``
+   - ``MongoDB\Laravel\Eloquent\MassPrunable``
+
+
+To learn more about the pruning feature, see `Pruning Models <https://laravel.com/docs/{+laravel-docs-version+}/eloquent#pruning-models>`__
+in the Laravel docs.
+
+Prunable Example
+~~~~~~~~~~~~~~~~
+
+The following prunable class includes a ``prunable()`` method that matches
+models that the prune action deletes and a ``pruning()`` method that runs
+before deleting a matching model:
+
+.. literalinclude:: /includes/eloquent-models/PlanetPrune.php
+   :language: php
+   :emphasize-lines: 6,10,12,18
+   :dedent:
+
+Mass Prunable Example
+~~~~~~~~~~~~~~~~~~~~~
+
+The following mass prunable class includes a ``prunable()`` method that matches
+models that the prune action deletes:
+
+.. literalinclude:: /includes/eloquent-models/PlanetMassPrune.php
+   :language: php
+   :emphasize-lines: 5,10,12
+   :dedent:
+