public function where($field, $key, $val)
    {
        $db = $this->load();
        $result = [];
        $values = [];
        if ($field === []) {
            foreach ($db as $index => $row) {
                if ($row[$key] === $val) {
                    foreach (array_keys($row) as $c) {
                        $values[$c] = $row[$c];
                    }
                    $result[$index] = $values;
                    $values = [];
                }
            }
        } else {
            foreach ($db as $index => $row) {
                if ($row[$key] === $val) {
                    foreach ((array) $field as $c) {
                        $values[$c] = $row[$c];
                    }
                    $result[$index] = $values;
                    $values = [];
                }
            }
        }
        return $result;
    }