DOCSP-37057 eloquent schema builder (#2776)

* DOCSP-37057: Eloquent schema builder

Author: Chris Cho

docs/eloquent-models.txt

@@ -0,0 +1,393 @@
+.. _laravel-schema-builder:
+
+==============
+Schema Builder
+==============
+
+.. facet::
+   :name: genre
+   :values: tutorial
+
+.. meta::
+   :keywords: php framework, odm, code example, schema facade, eloquent, blueprint, artisan, migrate
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 2
+   :class: singlecol
+
+Overview
+--------
+
+Laravel provides a **facade** to access the schema builder class ``Schema``,
+which lets you create and modify tables. Facades are static interfaces to
+classes that make the syntax more concise and improve testability.
+
+{+odm-short+} supports a subset of the index and collection management methods
+in the Laravel ``Schema`` facade.
+
+To learn more about facades, see `Facades <https://laravel.com/docs/{+laravel-docs-version+}/facades>`__
+in the Laravel documentation.
+
+The following sections describe the Laravel schema builder features available
+in {+odm-short+} and show examples of how to use them:
+
+- :ref:`<laravel-eloquent-migrations>`
+- :ref:`<laravel-eloquent-collection-exists>`
+- :ref:`<laravel-eloquent-indexes>`
+
+.. note::
+
+   {+odm-short+} supports managing indexes and collections, but
+   excludes support for MongoDB JSON schemas for data validation. To learn
+   more about JSON schema validation, see :manual:`Schema Validation </core/schema-validation/>`
+   in the {+server-docs-name+}.
+
+.. _laravel-eloquent-migrations:
+
+Perform Laravel Migrations
+--------------------------
+
+Laravel migrations let you programmatically create, modify, and delete
+your database schema by running methods included in the ``Schema`` facade.
+The following sections explain how to author a migration class when you use
+a MongoDB database and how to run them.
+
+Create a Migration Class
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can create migration classes manually or generate them by using the
+``php artisan make:migration`` command. If you generate them, you must make the
+following changes to perform the schema changes on your MongoDB database:
+
+- Replace the ``Illuminate\Database\Schema\Blueprint`` import with
+  ``MongoDB\Laravel\Schema\Blueprint`` if it is referenced in your migration
+- Use only commands and syntax supported by {+odm-short+}
+
+.. tip::
+
+   If your default database connection is set to anything other than your
+   MongoDB database, update the following setting to make sure the migration
+   specifies the correct database:
+
+   - Specify ``mongodb`` in the ``$connection`` field of your migration class
+   - Set ``DB_CONNECTION=mongodb`` in your ``.env`` configuration file
+
+The following example migration class contains the following methods:
+
+- ``up()``, which creates a collection and an index when you run the migration
+- ``down()``, which drops the collection and all the indexes on it when you roll back the migration
+
+.. literalinclude:: /includes/schema-builder/astronauts_migration.php
+   :dedent:
+   :language: php
+   :emphasize-lines: 6, 11
+
+Run or Roll Back a Migration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To run the database migration from a class file, run the following command
+after replacing the placeholder:
+
+.. code-block:: bash
+
+   php artisan migrate --path=<path to your migration class file>
+
+This command runs the ``up()`` function in the class file to create the
+collection and index in the database specified in the ``config/database.php``
+file.
+
+To roll back the migration, run the following command after replacing the
+placeholder:
+
+.. code-block:: bash
+
+   php artisan migrate:rollback --path=<path to your migration class file>
+
+This command runs the ``down()`` function in the class file to drop the
+collection and related indexes.
+
+To learn more about Laravel migrations, see
+`Database: Migrations <https://laravel.com/docs/{+laravel-docs-version+}/migrations>`__
+in the Laravel documentation.
+
+.. _laravel-eloquent-collection-exists:
+
+Check Whether a Collection Exists
+---------------------------------
+
+To check whether a collection exists, call the ``hasCollection()`` method on
+the ``Schema`` facade in your migration file. You can use this to
+perform migration logic conditionally.
+
+The following example migration creates a ``stars`` collection if a collection
+named ``telescopes`` exists:
+
+.. literalinclude:: /includes/schema-builder/stars_migration.php
+   :language: php
+   :dedent:
+   :start-after: begin conditional create
+   :end-before: end conditional create
+
+.. _laravel-eloquent-indexes:
+
+Manage Indexes
+--------------
+
+MongoDB indexes are data structures that improve query efficiency by reducing
+the number of documents needed to retrieve query results. Certain indexes, such
+as geospatial indexes, extend how you can query the data.
+
+To improve query performance by using an index, make sure the index covers
+the query. To learn more about indexes and query optimization, see the
+following {+server-docs-name+} entries:
+
+- :manual:`Indexes </indexes>`
+- :manual:`Query Optimization </core/query-optimization/>`
+
+The following sections show how you can use the schema builder to create and
+drop various types of indexes on a collection.
+
+Create an Index
+~~~~~~~~~~~~~~~
+
+To create indexes, call the ``create()`` method on the ``Schema`` facade
+in your migration file. Pass it the collection name and a callback
+method with a ``MongoDB\Laravel\Schema\Blueprint`` parameter. Specify the
+index creation details on the ``Blueprint`` instance.
+
+The following example migration creates indexes on the following collection
+fields:
+
+- Single field index on ``mission_type``
+- Compound index on ``launch_location`` and ``launch_date``, specifying a descending sort order on ``launch_date``
+- Unique index on the ``mission_id`` field, specifying the index name "unique_mission_id_idx"
+
+Click the :guilabel:`VIEW OUTPUT` button to see the indexes created by running
+the migration, including the default index on the ``_id`` field:
+
+.. io-code-block::
+
+   .. input:: /includes/schema-builder/flights_migration.php
+      :language: php
+      :dedent:
+      :start-after: begin create index
+      :end-before: end create index
+
+   .. output::
+      :language: json
+      :visible: false
+
+      [
+        { v: 2, key: { _id: 1 }, name: '_id_' },
+        { v: 2, key: { mission_type: 1 }, name: 'mission_type_1' },
+        {
+          v: 2,
+          key: { launch_location: 1, launch_date: -1 },
+          name: 'launch_location_1_launch_date_-1'
+        },
+        {
+          v: 2,
+          key: { mission_id: 1 },
+          name: 'unique_mission_id_idx',
+          unique: true
+        }
+      ]
+
+Specify Index Options
+~~~~~~~~~~~~~~~~~~~~~
+
+MongoDB index options determine how the indexes are used and stored.
+You can specify index options when calling an index creation method, such
+as ``index()``, on a ``Blueprint`` instance.
+
+The following migration code shows how to add a collation to an index as an
+index option. Click the :guilabel:`VIEW OUTPUT` button to see the indexes
+created by running the migration, including the default index on the ``_id``
+field:
+
+.. io-code-block::
+
+   .. input:: /includes/schema-builder/passengers_migration.php
+      :language: php
+      :dedent:
+      :start-after: begin index options
+      :end-before: end index options
+
+   .. output::
+      :language: json
+      :visible: false
+
+      [
+        { v: 2, key: { _id: 1 }, name: '_id_' },
+        {
+          v: 2,
+          key: { last_name: 1 },
+          name: 'passengers_collation_idx',
+          collation: {
+            locale: 'de@collation=phonebook',
+            caseLevel: false,
+            caseFirst: 'off',
+            strength: 3,
+            numericOrdering: true,
+            alternate: 'non-ignorable',
+            maxVariable: 'punct',
+            normalization: false,
+            backwards: false,
+            version: '57.1'
+          }
+        }
+      ]
+
+To learn more about index options, see :manual:`Options for All Index Types </reference/method/db.collection.createIndex/#options-for-all-index-types>`
+in the {+server-docs-name+}.
+
+Create Sparse, TTL, and Unique Indexes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can use {+odm-short+} helper methods to create the following types of
+indexes:
+
+- Sparse indexes, which allow index entries only for documents that contain the
+  specified field
+- Time-to-live (TTL) indexes, which expire after a set amount of time
+- Unique indexes, which prevent inserting documents that contain duplicate
+  values for the indexed field
+
+To create these index types, call the ``create()`` method on the ``Schema`` facade
+in your migration file. Pass ``create()`` the collection name and a callback
+method with a ``MongoDB\Laravel\Schema\Blueprint`` parameter. Call the
+appropriate helper method on the ``Blueprint`` instance and pass the
+index creation details.
+
+The following migration code shows how to create a sparse and a TTL index
+by using the index helpers. Click the :guilabel:`VIEW OUTPUT` button to see
+the indexes created by running the migration, including the default index on
+the ``_id`` field:
+
+.. io-code-block::
+
+   .. input:: /includes/schema-builder/planets_migration.php
+      :language: php
+      :dedent:
+      :start-after: begin index helpers
+      :end-before: end index helpers
+
+   .. output::
+      :language: json
+      :visible: false
+
+      [
+        { v: 2, key: { _id: 1 }, name: '_id_' },
+        { v: 2, key: { rings: 1 }, name: 'rings_1', sparse: true },
+        {
+          v: 2,
+          key: { last_visible_dt: 1 },
+          name: 'last_visible_dt_1',
+          expireAfterSeconds: 86400
+        }
+      ]
+
+You can specify sparse, TTL, and unique indexes on either a single field or
+compound index by specifying them in the index options.
+
+The following migration code shows how to create all three types of indexes
+on a single field. Click the :guilabel:`VIEW OUTPUT` button to see the indexes
+created by running the migration, including the default index on the ``_id``
+field:
+
+.. io-code-block::
+
+   .. input:: /includes/schema-builder/planets_migration.php
+      :language: php
+      :dedent:
+      :start-after: begin multi index helpers
+      :end-before: end multi index helpers
+
+   .. output::
+      :language: json
+      :visible: false
+
+      [
+        { v: 2, key: { _id: 1 }, name: '_id_' },
+        {
+          v: 2,
+          key: { last_visible_dt: 1 },
+          name: 'last_visible_dt_1',
+          unique: true,
+          sparse: true,
+          expireAfterSeconds: 3600
+        }
+      ]
+
+To learn more about these indexes, see :manual:`Index Properties </core/indexes/index-properties/>`
+in the {+server-docs-name+}.
+
+Create a Geospatial Index
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In MongoDB, geospatial indexes let you query geospatial coordinate data for
+inclusion, intersection, and proximity.
+
+To create geospatial indexes, call the ``create()`` method on the ``Schema`` facade
+in your migration file. Pass ``create()`` the collection name and a callback
+method with a ``MongoDB\Laravel\Schema\Blueprint`` parameter. Specify the
+geospatial index creation details on the ``Blueprint`` instance.
+
+The following example migration creates a ``2d`` and ``2dsphere`` geospatial
+index on the ``spaceports`` collection. Click the :guilabel:`VIEW OUTPUT`
+button to see the indexes created by running the migration, including the
+default index on the ``_id`` field:
+
+.. io-code-block::
+   .. input:: /includes/schema-builder/spaceports_migration.php
+      :language: php
+      :dedent:
+      :start-after: begin create geospatial index
+      :end-before: end create geospatial index
+
+   .. output::
+      :language: json
+      :visible: false
+
+      [
+        { v: 2, key: { _id: 1 }, name: '_id_' },
+        {
+          v: 2,
+          key: { launchpad_location: '2dsphere' },
+          name: 'launchpad_location_2dsphere',
+          '2dsphereIndexVersion': 3
+        },
+        { v: 2, key: { runway_location: '2d' }, name: 'runway_location_2d' }
+      ]
+
+
+To learn more about geospatial indexes, see
+:manual:`Geospatial Indexes </core/indexes/index-types/index-geospatial/>` in
+the {+server-docs-name+}.
+
+Drop an Index
+~~~~~~~~~~~~~
+
+To drop indexes from a collection, call the ``table()`` method on the
+``Schema`` facade in your migration file. Pass it the table name and a
+callback method with a ``MongoDB\Laravel\Schema\Blueprint`` parameter.
+Call the ``dropIndex()`` method with the index name on the ``Blueprint``
+instance.
+
+.. note::
+
+   If you drop a collection, MongoDB automatically drops all the indexes
+   associated with it.
+
+The following example migration drops an index called ``unique_mission_id_idx``
+from the ``flights`` collection:
+
+.. literalinclude:: /includes/schema-builder/flights_migration.php
+   :language: php
+   :dedent:
+   :start-after: begin drop index
+   :end-before: end drop index
+
+