Granada\ORM::_create_placeholders PHP Method

    protected function _create_placeholders($fields)
    {
        if (!empty($fields)) {
            $db_fields = array();
            foreach ($fields as $key => $value) {
                // Process expression fields directly into the query
                if (array_key_exists($key, $this->_expr_fields)) {
                    $db_fields[] = $value;
                } else {
                    $db_fields[] = '?';
                }
            }
            return implode(', ', $db_fields);
        }
    }