The CakePHP ORM provides a powerful and flexible way to work with relational databases. Using a datamapper pattern the ORM allows you to manipulate data as entities allowing you to create expressive domain layers in your applications.

The CakePHP ORM is compatible with:

• MySQL 5.1+
• Postgres 8+
• SQLite3
• SQLServer 2008+
• Oracle (through a community plugin)

The first thing you need to do when using this library is register a connection object. Before performing any operations with the connection, you need to specify a driver to use:

use Cake\Datasource\ConnectionManager;

ConnectionManager::setConfig('default', [
	'className' => \Cake\Database\Connection::class,
	'driver' => \Cake\Database\Driver\Mysql::class,
	'database' => 'test',
	'username' => 'root',
	'password' => 'secret',
	'cacheMetadata' => true,
	'quoteIdentifiers' => false,
]);

Once a 'default' connection is registered, it will be used by all the Table mappers if no explicit connection is defined.

In order to access table instances you need to use a Table Locator.

use Cake\ORM\Locator\TableLocator;

$locator = new TableLocator();
$articles = $locator->get('Articles');

You can also use a trait for easy access to the locator instance:

use Cake\ORM\Locator\LocatorAwareTrait;

$articles = $this->getTableLocator()->get('Articles');

By default, classes using LocatorAwareTrait will share a global locator instance. You can inject your own locator instance into the object:

use Cake\ORM\Locator\TableLocator;
use Cake\ORM\Locator\LocatorAwareTrait;

$locator = new TableLocator();
$this->setTableLocator($locator);

$articles = $this->getTableLocator()->get('Articles');

In your table classes you can define the relations between your tables. CakePHP's ORM supports 4 association types out of the box:

• belongsTo - E.g. Many articles belong to a user.
• hasOne - E.g. A user has one profile.
• hasMany - E.g. A user has many articles.
• belongsToMany - E.g. An article belongsToMany tags.

You define associations in your table's initialize() method. See the documentation for complete examples.

Once you've defined some table classes you can read existing data in your tables:

use Cake\ORM\Locator\LocatorAwareTrait;

$articles = $this->getTableLocator()->get('Articles');
foreach ($articles->find() as $article) {
	echo $article->title;
}

You can use the query builder to create complex queries, and a variety of methods to access your data.

Table objects provide ways to convert request data into entities, and then persist those entities to the database:

use Cake\ORM\Locator\LocatorAwareTrait;

$data = [
	'title' => 'My first article',
	'body' => 'It is a great article',
	'user_id' => 1,
	'tags' => [
		'_ids' => [1, 2, 3]
	],
	'comments' => [
		['comment' => 'Good job'],
		['comment' => 'Awesome work'],
	]
];

$articles = $this->getTableLocator()->get('Articles');
$article = $articles->newEntity($data, [
	'associated' => ['Tags', 'Comments']
]);
$articles->save($article, [
	'associated' => ['Tags', 'Comments']
])

The above shows how you can easily marshal and save an entity and its associations in a simple & powerful way. Consult the ORM documentation for more in-depth examples.

Once you have a reference to an entity, you can use it to delete data:

$articles = $this->getTableLocator()->get('Articles');
$article = $articles->get(2);
$articles->delete($article);

It is recommended to enable metadata cache for production systems to avoid performance issues. For e.g. file system strategy your bootstrap file could look like this:

use Cake\Cache\Engine\FileEngine;

$cacheConfig = [
   'className' => FileEngine::class,
   'duration' => '+1 year',
   'serialize' => true,
   'prefix'    => 'orm_',
];
Cache::setConfig('_cake_model_', $cacheConfig);

Cache configs are optional, so you must require cachephp/cache to add one.

By default, the Cake ORM uses the \Cake\ORM\Table and \Cake\ORM\Entity classes to interact with the database. While using the default classes makes sense for quick scripts and small applications, you will often want to use your own classes for adding your custom logic.

When using the ORM as a standalone package, you are free to choose where to store these classes. For example, you could use the Data folder for this:

<?php
// in src/Data/Table/ArticlesTable.php
namespace Acme\Data\Table;

use Acme\Data\Entity\Article;
use Acme\Data\Table\UsersTable;
use Cake\ORM\Table;

class ArticlesTable extends Table
{
    public function initialize()
    {
        $this->setEntityClass(Article::class);
        $this->belongsTo('Users', ['className' => UsersTable::class]);
    }
}

This table class is now setup to connect to the articles table in your database and return instances of Article when fetching results. In order to get an instance of this class, as shown before, you can use the TableLocator:

<?php
use Acme\Data\Table\ArticlesTable;
use Cake\ORM\Locator\TableLocator;

$locator = new TableLocator();
$articles = $locator->get('Articles', ['className' => ArticlesTable::class]);

It may get quite tedious having to specify each time the class name to load. So the Cake ORM can do most of the work for you if you give it some configuration.

The convention is to have all ORM related classes inside the src/Model folder, that is the Model sub-namespace for your app. So you will usually have the src/Model/Table and src/Model/Entity folders in your project. But first, we need to inform Cake of the namespace your application lives in:

<?php
use Cake\Core\Configure;

Configure::write('App.namespace', 'Acme');

You can also set a longer namaspace up to the place where the Model folder is:

<?php
use Cake\Core\Configure;

Configure::write('App.namespace', 'My\Log\SubNamespace');

Consult the CakePHP ORM documentation for more in-depth documentation.