This is recipe for using Doctrine 2 in your [CodeIgniter](http://www.codeigniter.com) framework.

> **NOTE**
>
> This might not work for all CodeIgniter versions and may require slight adjustments.

Here is how to set it up:

Make a CodeIgniter library that is both a wrapper and a bootstrap for Doctrine 2.

++ Setting up the file structure

Here are the steps:

* Add a php file to your system/application/libraries folder called Doctrine.php. This is going to be your wrapper/bootstrap for the D2 entity manager.
* Put the Doctrine folder (the one that contains Common, DBAL, and ORM) inside that same libraries folder.
* Your system/application/libraries folder now looks like this:

    system/applications/libraries
    -Doctrine
    -Doctrine.php
    -index.html

* If you want, open your config/autoload.php file and autoload your Doctrine library.

    [php]
    $autoload['libraries'] = array('doctrine');

++ Creating your Doctrine CodeIgniter library

Now, here is what your Doctrine.php file should look like. Customize it to your needs.

    [php]
    use Doctrine\Common\ClassLoader,
        Doctrine\ORM\Configuration,
        Doctrine\ORM\EntityManager,
        Doctrine\Common\Cache\ArrayCache,
        Doctrine\DBAL\Logging\EchoSqlLogger;

    class Doctrine {

      public $em = null;

      public function __construct()
      {
        // load database configuration from CodeIgniter
        require_once APPPATH.'config/database.php';

        // Set up class loading. You could use different autoloaders, provided by your favorite framework,
        // if you want to.
        require_once APPPATH.'libraries/Doctrine/Common/ClassLoader.php';

        $doctrineClassLoader = new ClassLoader('Doctrine',  APPPATH.'libraries');
        $doctrineClassLoader->register();
        $entitiesClassLoader = new ClassLoader('models', rtrim(APPPATH, "/" ));
        $entitiesClassLoader->register();
        $proxiesClassLoader = new ClassLoader('Proxies', APPPATH.'models/proxies');
        $proxiesClassLoader->register();

        // Set up caches
        $config = new Configuration;
        $cache = new ArrayCache;
        $config->setMetadataCacheImpl($cache);
        $config->setQueryCacheImpl($cache);

        // Proxy configuration
        $config->setProxyDir(APPPATH.'/models/proxies');
        $config->setProxyNamespace('Proxies');

        // Set up logger
        $logger = new EchoSqlLogger;
        $config->setSqlLogger($logger);

        $config->setAutoGenerateProxyClasses( TRUE );

        // Database connection information
        $connectionOptions = array(
            'driver' => 'pdo_mysql',
            'user' =>     $db['default']['username'],
            'password' => $db['default']['password'],
            'host' =>     $db['default']['hostname'],
            'dbname' =>   $db['default']['database']
        );

        // Create EntityManager
        $this->em = EntityManager::create($connectionOptions, $config);
      }
    }

Please note that this is a development configuration; for a production system you'll want to use a real caching system like APC, get rid of EchoSqlLogger, and turn off autoGenerateProxyClasses.

For more details, consult the [Doctrine 2 Configuration documentation](http://www.doctrine-project.org/documentation/manual/2_0/en/configuration#configuration-options).

++ Now to use it

Whenever you need a reference to the entity manager inside one of your controllers, views, or models you can do this:

    [php]
    $em = $this->doctrine->em;

That's all there is to it. Once you get the reference to your EntityManager do your Doctrine 2.0 voodoo as normal.

Note: If you do not choose to autoload the Doctrine library, you will need to put this line before you get a reference to it:

    [php]
    $this->load->library('doctrine');

Good luck!