gistfile1.php

<?php
use Phalcon\Db\RawValue,
  Phalcon\Mvc\Model\Message,
  Phalcon\Mvc\Model\Relation;
	
abstract class Model extends \Phalcon\Mvc\Model {
  
	/**
	 * @see https://github.com/phalcon/cphalcon/issues/2039 
	 */
	protected function _checkForeignKeysRestrict() {
		$manager   = $this->_modelsManager;
		$belongsTo = $manager->getBelongsTo($this);
		
		if (! empty ($belongsTo)) {
			$nullFields = array_flip(array_diff(
				$this->getModelsMetaData()->getAttributes($this),
				$this->getModelsMetaData()->getNotNullAttributes($this)
			));

			$isNotNullFk = function ($field, $value) use ($nullFields) {
				if (isset ($nullFields[$field]) && (
					$value === NULL ||
					($value instanceof RawValue && strtolower($value) === 'null'))) {

					return FALSE;
				}

				return TRUE;
			};

			foreach ($belongsTo as $relation) {
				$foreignKey = $relation->getForeignKey();

				$action = $foreignKey !== FALSE;

				if ($action && is_array($foreignKey) && isset ($foreignKey['action'])) {
					$action = $foreignKey['action'] === Relation::ACTION_RESTRICT;
				}
				
				if ($action) {
					$conditions       = [];
					$bindParams       = [];
					$fields           = $relation->getFields();
					$referencedFields = $relation->getReferencedFields();

					if (is_array($fields)) {
						foreach ($fields as $position => $field) {
							if ($isNotNullFk($field, $this->{$field})) {
								$conditions[] = '[' . $referencedFields[$position] . '] = ?' . $position;
								$bindParams[] = $this->{$field};
							}
						}
					}
					else if ($isNotNullFk($fields, $this->{$fields})) {
						$conditions[] = '[' . $referencedFields . '] = ?0';
						$bindParams[] = $this->{$fields};
					}

					if (isset ($foreignKey['conditions'])) {
						$conditions[] = $foreignKey['conditions'];
					}

					if ($conditions === []) {
						continue;
					}

					if (! $manager->load($relation->getReferencedModel())->count([join(' AND ', $conditions), 'bind' => $bindParams])) {
						if (! isset ($foreignKey['message'])) {
							if (is_array($fields)) {
								$message = 'Value of fields "' . join(', ', $fields) . '" does not exist on referenced table';
							}
							else {
								$message = 'Value of field "' . $fields . '" does not exist on referenced table';
							}
						}
						else {
							$message = $foreignKey['message'];
						}

						$this->appendMessage(new Message($message, $fields, 'ConstraintViolation'));

						if (ini_get('phalcon.orm.events')) {
							$this->fireEvent('onValidationFails');
							$this->_cancelOperation();
						}

						return FALSE;
					}
				}
			}
		}

		return TRUE;
	}

}