如何在Doctrine 2中使用OneToMany关系更新记录？

/**
 * 
 * @param \\Doctring\\Common\\Collections\\Collection $property
 * @OneToMany(targetEntity=\"Countries\",mappedBy=\"user\", cascade={\"persist\", \"remove\"})
 */
private $countries;

public function updateUser($user) {
    $entity = $this->getUser($user[\'id\']);
    if (!$entity)
        throw new Exception(\'Error saving user!\');
    $countries = $this->getCountriesArray($user); //countries already set in the db
    $tempCountries = array();
    $delete = array();
    foreach ($countries as $country) {
        $found = false;
        if (in_array($country, $user[\'countries\'])) {
            $tempCountries[] = $country;
        } else {
            $delete[] = $country;
        }
    }
    $tempCountries = array_unique(array_merge(                //combine the countries from the db we want to leave 
                                        $tempCountries,       //with those the user selected
                                        $user[\'countries\']));
    ...
    //here I need something to remove the countries in $delete...right?
    ...
    $entity->setEmail($user[\'email\']);
    $entity->setResponsable($user[\'responsable\']);
    $entity->setPassword($this->createPass($user[\'password\']));
    $entity->setUrl($user[\'url\']);
    $entity->setRole($user[\'role\']);

    $modelCountries = array();
    foreach($tempCountries as $c) {
        $p = new Countries();
        $p->setCountryName($c);
        $p->setUser($entity);
        $modelCountries[] = $p;
    }
    $entity->setCountries($modelCountries);

    $this->em->persist($entity);
    $this->em->flush();
}