/**
  * @param BaseEntity $entity
  * @return mixed
  */
 public function update($entity)
 {
     $entityName = Database::getEntityName($this->definition->name);
     $builder = Database::update()->table($entityName)->where("{$entityName}.{$this->definition->primaryKey} = {$entity->id}");
     foreach ($entity->felder as $name => $feld) {
         if ($feld->isWritable()) {
             $builder->field($name, $feld);
         }
     }
     $builder->execute();
 }