Monitor:
  actAs:
    Timestampable: ~
  columns:
    label: {type: string(45)}
    url: {type: string(80)}
    frequency: {type: integer}
    timeout: {type: integer}
    method: {type: enum, values: [GET, POST]}
    parameters: {type: string(255)}
  relations:
    Server:
      foreignAlias: Servers
      refClass: Benchmark
      local: monitor_id
      foreign: server_id

Server:
  actAs:
    Timestampable: ~
  columns:
    name: string(255)
    ip: string(255)
  relations:
     Monitor:
      foreignAlias: Monitors
      refClass: Benchmark
      local: server_id
      foreign: monitor_id

Benchmark:
  actAs:
    Timestampable: ~
  columns:
    monitor_id: { type: integer, primary: true }
    server_id: { type: integer, primary: true }
    connexionTime: {type: string(45)}
    executionTime: {type: string(45)}
    responseTime: {type: string(45)}
    responseCode: {type: string(45)}
    responseMessage: {type: string(45)}
  relations:
    Monitor:
      local: monitor_id
      foreign: id
      foreignAlias: Monitors
    Server:
      local: server_id
      foreign: id
      foreignAlias: Servers

500 | Internal Server Error | Doctrine_Connection_Mysql_Exception
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`sfmonitoring`.`benchmark`, CONSTRAINT `benchmark_monitor_id_monitor_id` FOREIGN KEY (`monitor_id`) REFERENCES `monitor` (`id`))

abstract class BaseBenchmarkForm extends BaseFormDoctrine
{
  public function setup()
  {
    $this->setWidgets(array(
      'monitor_id'      => new sfWidgetFormInputHidden(),
      'server_id'       => new sfWidgetFormInputHidden(),
      'connexionTime'   => new sfWidgetFormInputText(),
      'executionTime'   => new sfWidgetFormInputText(),
      'responseTime'    => new sfWidgetFormInputText(),
      'responseCode'    => new sfWidgetFormInputText(),
      'responseMessage' => new sfWidgetFormInputText(),
      'created_at'      => new sfWidgetFormDateTime(),
      'updated_at'      => new sfWidgetFormDateTime(),
    ));

    $this->setValidators(array(
      'monitor_id'      => new sfValidatorChoice(array('choices' => array($this->getObject()->get('monitor_id')), 'empty_value' => $this->getObject()->get('monitor_id'), 'required' => false)),
      'server_id'       => new sfValidatorChoice(array('choices' => array($this->getObject()->get('server_id')), 'empty_value' => $this->getObject()->get('server_id'), 'required' => false)),
      'connexionTime'   => new sfValidatorString(array('max_length' => 45, 'required' => false)),
      'executionTime'   => new sfValidatorString(array('max_length' => 45, 'required' => false)),

Monitor:
      tableName: monitor
      actAs:
        Timestampable: ~
      columns:
        label: {type: string(45)}
        url: {type: string(80)}
        frequency: {type: integer}
        timeout: {type: integer}
        method: {type: enum, values: [GET, POST]}
        parameters: {type: string(255)}

    Benchmark:
      actAs:
        Timestampable: ~
      columns:
        monitor_id: { type: integer, primary: true }
        server_id: { type: integer, primary: true }
        connexionTime: {type: string(45)}
        executionTime: {type: string(45)}
        responseTime: {type: string(45)}
        responseCode: {type: string(45)}
        responseMessage: {type: string(45)}
      relations:
        Monitor: { onDelete: CASCADE, local: monitor_id, foreign: id, foreignAlias: Monitors }
        Server: { onDelete: CASCADE, local: server_id, foreign: id, foreignAlias: Servers }

    Server:
      actAs:
        Timestampable: ~
      columns:
        name: string(255)
        ip: string(255)

public function configure() {
  parent::configure();
  $this->widgetSchema['monitor_id'] = sfWidgetFormDoctrineChoice(array('model' => 'Monitor'));
  $this->widgetSchema['server_id'] = sfWidgetFormDoctrineChoice(array('model' => 'Server'));

  $this->validatorSchema['monitor_id'] = sfValidatorDoctrineChoice(array('model' => 'Monitor'));
  $this->validatorSchema['server_id'] = sfValidatorDoctrineChoice(array('model' => 'Server'));

}