public function relationsErrors(\Asgard\Entity\Entity $entity, $groups=[]) {
		$data = [];
		$validator = $this->createValidator($entity);
		$validator->set('entity', $entity);
		$validator->set('dataMapper', $this);
		foreach($this->relations($this->getEntityDefinition($entity)) as $name=>$relation) {
			$data[$name] = $entity->get($name, null, false);
			$relation->prepareValidator($validator->attribute($name));
			$property = $this->getEntityDefinition($entity)->property($name);
			$validator->attribute($name)->ruleMessages($property->getMessages());
			$validator->attribute($name)->isNull(function(){return false;});
		}

		return $validator->errors($data, $groups);
	}