protected function registerEntityManagers(array $settings)
    {
        if (array_key_exists('connection', $settings)) {
            $settings = [$settings];
        }

        foreach ($settings as $name => $config) {
            if (!is_string($name)) {
                $name = $this->getOption(static::RELATIONAL_MANAGER_NAME);
            }

            $this->addBuilder(new RelationalBuilder($config, $name));
        }
    }