yii\gii\generators\model\Generator::validateDb PHP Method

    public function validateDb()
    {
        if (!Yii::$app->has($this->db)) {
            $this->addError('db', 'There is no application component named "db".');
        } elseif (!Yii::$app->get($this->db) instanceof Connection) {
            $this->addError('db', 'The "db" application component must be a DB connection instance.');
        }
    }

 /**
  * Validates the [[db]] attribute.
  */
 public function validateDb()
 {
     if (Yii::$container->has($this->db)) {
         return true;
     } else {
         return parent::validateDb();
     }
 }