ruby on rails 更新记录

更新符合条件的记录：
result = true;
begin
Public::Score.update_all("checked=true","group_id=#{group_id} and teacher_id=#{teacher_id}" );
rescue
＃ 异常
result = false
end

更新某一记录某一字段值：
field_id = 100
#field_id为数据表的的主键字段的值
Public::Condition.update(field_id, {'check_time' => Time.now})