framework/db/Schema.php
protected function normalizePdoRowKeyCase(array $row, $multiple)
    {
        if ($this->db->getSlavePdo()->getAttribute(\PDO::ATTR_CASE) !== \PDO::CASE_UPPER) {
            return $row;
        }

        if ($multiple) {
            return array_map(function (array $row) {
                return array_change_key_case($row, CASE_LOWER);
            }, $row);
        }

        return array_change_key_case($row, CASE_LOWER);
    }
protected function normalizePdoRowKeyCase(array $row, $multiple)
    {
        if ($this->db->getSlavePdo()->getAttribute(\PDO::ATTR_CASE) !== \PDO::CASE_UPPER) {
            return $row;
        }

        if ($multiple) {
            return array_map(function (array $row) {
                return array_change_key_case($row, CASE_LOWER);
            }, $row);
        }

        return array_change_key_case($row, CASE_LOWER);
    }
Changes row's array key case to lower if PDO's one is set to uppercase.
@param array $row row's array or an array of row's arrays.
@param bool $multiple whether multiple rows or a single row passed.
@return array normalized row or rows.
@since 2.0.13