/**
  * @return \yii\db\ActiveQuery
  */
 public function getRentals()
 {
     return $this->hasMany(Rental::className(), ['staff_id' => 'staff_id']);
 }
 /**
  * @return \yii\db\ActiveQuery
  */
 public function getRental()
 {
     return $this->hasOne(Rental::className(), ['rental_id' => 'rental_id']);
 }
 /**
  * @return \yii\db\ActiveQuery
  */
 public function getRentals()
 {
     return $this->hasMany(Rental::className(), ['customer_id' => 'customer_id']);
 }
 /**
  * @return \yii\db\ActiveQuery
  */
 public function getRentals()
 {
     return $this->hasMany(Rental::className(), ['inventory_id' => 'inventory_id']);
 }