minor #16924 [Doctrine] Deprecate the reverse engineering docs (javiereguiluz)

This PR was merged into the 4.4 branch.

Discussion
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[Doctrine] Deprecate the reverse engineering docs

Fixes #16903.

Commits
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9ed3b06 [Doctrine] Deprecate the reverse engineering docs

Author: xabbuh

doctrine/reverse_engineering.rst

@@ -4,114 +4,13 @@
 How to Generate Entities from an Existing Database
 ==================================================
 
-When starting work on a brand new project that uses a database, two different
-situations can occur. In most cases, the database model is designed
-and built from scratch. Sometimes, however, you'll start with an existing and
-probably unchangeable database model. Fortunately, Doctrine comes with a bunch
-of tools to help generate model classes from your existing database.
+.. caution::
 
-.. note::
+    The ``doctrine:mapping:import`` command used to generate Doctrine entities
+    from existing databases was deprecated by Doctrine in 2019 and it's no
+    longer recommended to use it.
 
-    As the `Doctrine tools documentation`_ says, reverse engineering is a
-    one-time process to get started on a project. Doctrine is able to convert
-    approximately 70-80% of the necessary mapping information based on fields,
-    indexes and foreign key constraints. Doctrine can't discover inverse
-    associations, inheritance types, entities with foreign keys as primary keys
-    or semantical operations on associations such as cascade or lifecycle
-    events. Some additional work on the generated entities will be necessary
-    afterwards to design each to fit your domain model specificities.
+    Instead, you can use the ``make:entity`` command from `Symfony Maker Bundle`_
+    to quickly generate the Doctrine entities of your application.
 
-This tutorial assumes you're using a simple blog application with the following
-two tables: ``blog_post`` and ``blog_comment``. A comment record is linked
-to a post record thanks to a foreign key constraint.
-
-.. code-block:: sql
-
-    CREATE TABLE `blog_post` (
-      `id` bigint(20) NOT NULL AUTO_INCREMENT,
-      `title` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
-      `content` longtext COLLATE utf8_unicode_ci NOT NULL,
-      `created_at` datetime NOT NULL,
-      PRIMARY KEY (`id`)
-    ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
-
-    CREATE TABLE `blog_comment` (
-      `id` bigint(20) NOT NULL AUTO_INCREMENT,
-      `post_id` bigint(20) NOT NULL,
-      `author` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
-      `content` longtext COLLATE utf8_unicode_ci NOT NULL,
-      `created_at` datetime NOT NULL,
-      PRIMARY KEY (`id`),
-      KEY `blog_comment_post_id_idx` (`post_id`),
-      CONSTRAINT `blog_post_id` FOREIGN KEY (`post_id`) REFERENCES `blog_post` (`id`) ON DELETE CASCADE
-    ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
-
-Before diving into the recipe, be sure your database connection parameters are
-correctly set up in the ``.env`` file (or ``.env.local`` override file).
-
-The first step towards building entity classes from an existing database
-is to ask Doctrine to introspect the database and generate the corresponding
-metadata files. Metadata files describe the entity class to generate based on
-table fields.
-
-.. code-block:: terminal
-
-    $ php bin/console doctrine:mapping:import "App\Entity" annotation --path=src/Entity
-
-This command line tool asks Doctrine to introspect the database and generate
-new PHP classes with annotation metadata into ``src/Entity``. This generates two
-files: ``BlogPost.php`` and ``BlogComment.php``.
-
-.. tip::
-
-    It's also possible to generate the metadata files into XML or eventually into YAML:
-
-    .. code-block:: terminal
-
-        $ php bin/console doctrine:mapping:import "App\Entity" xml --path=config/doctrine
-
-    In this case, make sure to adapt your mapping configuration accordingly:
-
-    .. code-block:: yaml
-
-        # config/packages/doctrine.yaml
-        doctrine:
-            # ...
-            orm:
-                # ...
-                mappings:
-                    App:
-                        is_bundle: false
-                        type: xml # "yml" is marked as deprecated for doctrine v2.6+ and will be removed in v3
-                        dir: '%kernel.project_dir%/config/doctrine'
-                        prefix: 'App\Entity'
-                        alias: App
-
-Generating the Getters & Setters or PHP Classes
------------------------------------------------
-
-The generated PHP classes now have properties and annotation metadata, but they
-do *not* have any getter or setter methods. If you generated XML or YAML metadata,
-you don't even have the PHP classes!
-
-To generate the missing getter/setter methods (or to *create* the classes if necessary),
-run:
-
-.. code-block:: terminal
-
-    // generates getter/setter methods for all Entities
-    $ php bin/console make:entity --regenerate App
-
-    // generates getter/setter methods for one specific Entity
-    $ php bin/console make:entity --regenerate "App\Entity\Country"
-
-.. note::
-
-    If you want to have a OneToMany relationship, you will need to add
-    it manually into the entity (e.g. add a ``comments`` property to ``BlogPost``)
-    or to the generated XML or YAML files. Add a section on the specific entities
-    for one-to-many defining the ``inversedBy`` and the ``mappedBy`` pieces.
-
-The generated entities are now ready to be used. Have fun!
-
-.. _`Doctrine tools documentation`: https://www.doctrine-project.org/projects/doctrine-orm/en/current/reference/tools.html#reverse-engineering
+.. _`Symfony Maker Bundle`: https://symfony.com/bundles/SymfonyMakerBundle/current/index.html