/**
  * {@inheritDoc}
  */
 public function addConstraint(Constraint\ConstraintInterface $constraint)
 {
     if (!in_array($constraint->getName(), $this->_type->validConstraints())) {
         throw new \LogicException('Constraints of type `' . $constraint->getName() . '` cannot be set on rewards with a type of `' . $this->_type->getName() . '`');
     }
     if (null === $this->_constraints) {
         $this->_constraints = new Constraint\Collection();
     }
     $this->_constraints->add($constraint);
 }
 /**
  * Add query saving the constraint name and value, as well as the reward config ID, to the database transaction
  *
  * @param ConfigInterface $config
  * @param ConstraintInterface $constraint
  */
 private function _addToTransaction(ConfigInterface $config, ConstraintInterface $constraint)
 {
     $this->_transaction->add("\n\t\t\tINSERT INTO\n\t\t\t\trefer_a_friend_reward_constraint\n\t\t\t\t(\n\t\t\t\t\treward_config_id,\n\t\t\t\t\t`name`,\n\t\t\t\t\t`value`\n\t\t\t\t)\n\t\t\t\tVALUES\n\t\t\t\t(\n\t\t\t\t\t:rewardConfigID?i,\n\t\t\t\t\t:name?s,\n\t\t\t\t\t:value?s\n\t\t\t\t)\n\t\t", ['rewardConfigID' => $config->getID(), 'name' => $constraint->getName(), 'value' => $constraint->getValue()]);
 }