How to use multiple databases dynamically for one model in CakePHP

This gentleman (Olivier) had the same problem! (A year ago) He wrote a small adaptation for the Controllers! It's pretty small and it turns out, it works in 1.3 and 2.x.

Anyhow, this is my final solution, that I put in the app/Model/AppModel.php:

class AppModel extends Model
{
  /**
   * Connects to specified database
   *
   * @param String name of different database to connect with.
   * @param String name of existing datasource
   * @return boolean true on success, false on failure
   * @access public
   */
    public function setDatabase($database, $datasource = 'default')
    {
      $nds = $datasource . '_' . $database;      
      $db  = &ConnectionManager::getDataSource($datasource);

      $db->setConfig(array(
        'name'       => $nds,
        'database'   => $database,
        'persistent' => false
      ));

      if ( $ds = ConnectionManager::create($nds, $db->config) ) {
        $this->useDbConfig  = $nds;
        $this->cacheQueries = false;
        return true;
      }

      return false;
    }
}

And here is how I used it in my app/Controller/CarsController.php:

class CarsController extends AppController
{
  public function index()
  {
    $this->Car->setDatabase('cake_sandbox_client3');

    $cars = $this->Car->find('all');

    $this->set('cars', $cars);
  }

}

I'm betting, I'm not the first or last one with this problem. So I really hope this information will find people & the CakePHP community.

I don't like the idea of writing down the actual name of the database in the code. For multiple databases, you have the database.php file where you can set as many databases as you need.

If you want to "switch" a database for a specific model on the fly, use the setDataSource method. (see here)

For example, if you have two databases, you can define them in the database.php file as "default" and "sandbox", as an example.

Then, in your code:

$this->Car->setDataSource('sandbox');

The sandbox is the name of the configuration, and the actual name of the database is written only once in the database.php file.

You can always query any databases using full notation in mysql. F.ex.:

SELECT * FROM my_schema_name.table_name;

Cake way:

$db = $this->getDataSource();
$query = array(
    'fields' => array('*'),
    'table' => 'my_schema_name.table_name'
);
$stmt = $db->buildStatement($query, $this);
$result = $db->execute($stmt);

In your database.php

public $mongo = array(
    'datasource' => 'Mongodb.MongodbSource',
    'database' => 'database_name_mongo',
    'host' => 'localhost',
    'port' => 27017,
);

In your controller you can use

$this->Organisation->setDataSource('mongo');

then apply query like

this->Organisation->find('all');

This is a folk of the accepted answer. This will prevent the error if the new datasource has already existed:

public function setDatabase($database, $datasource = 'default')
{
    $newDatasource = $datasource . '_' . $database;
    try {
        // return the new datasource if it's already existed
        $db = ConnectionManager::getDataSource($newDatasource);
        $this->useDbConfig  = $newDatasource;
        $this->cacheQueries = false;
        return true;
    } catch (Exception $e) {
        // debug($e->getMessage());
    }

    $db  = ConnectionManager::getDataSource($datasource);
    $db->setConfig(array(
        'name'       => $newDatasource,
        'database'   => $database,
        'persistent' => false
    ));

    if ( $ds = ConnectionManager::create($newDatasource, $db->config) ) {
        $this->useDbConfig  = $newDatasource;
        $this->cacheQueries = false;
        return true;
    }

    return false;
}