ActiveRecord\Validations::validates_uniqueness_of PHP Method

    public function validates_uniqueness_of($attrs)
    {
        $configuration = array_merge(self::$DEFAULT_VALIDATION_OPTIONS, array('message' => Errors::$DEFAULT_ERROR_MESSAGES['unique']));
        // Retrieve connection from model for quote_name method
        $connection = $this->klass->getMethod('connection')->invoke(null);
        foreach ($attrs as $attr) {
            $options = array_merge($configuration, $attr);
            $pk = $this->model->get_primary_key();
            $pk_value = $this->model->{$pk[0]};
            if (is_array($options[0])) {
                $add_record = join("_and_", $options[0]);
                $fields = $options[0];
            } else {
                $add_record = $options[0];
                $fields = array($options[0]);
            }
            $sql = "";
            $conditions = array("");
            $pk_quoted = $connection->quote_name($pk[0]);
            if ($pk_value === null) {
                $sql = "{$pk_quoted} IS NOT NULL";
            } else {
                $sql = "{$pk_quoted} != ?";
                array_push($conditions, $pk_value);
            }
            foreach ($fields as $field) {
                $field = $this->model->get_real_attribute_name($field);
                $quoted_field = $connection->quote_name($field);
                $sql .= " AND {$quoted_field}=?";
                array_push($conditions, $this->model->{$field});
            }
            $conditions[0] = $sql;
            if ($this->model->exists(array('conditions' => $conditions))) {
                $this->record->add($add_record, $options['message']);
            }
        }
    }