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上课形式有很多种,不同的上课形式对应不同的科目,不同的科目对应不同的课程......
这些数据要怎么读取比较合适??

打算用的做法(
当用户点击下拉按钮时,通过ajax将上课形式的的值填充进去.
点击科目下拉按钮时,根据上课形式的选择,在通过ajax将科目的值填充进去
点一次,查一次
)


回复讨论(解决方案)

查表呗,每个上课形式都对应相应的科目

查表呗,每个上课形式都对应相应的科目



那些数据要一次性读出来,还是根据前一次选择,读取下一个??

你的 科目隶属于上课形式,课程隶属于科目
科目还没选定,你怎么取课程?

你的 科目隶属于上课形式,课程隶属于科目
科目还没选定,你怎么取课程?

你的 科目隶属于上课形式,课程隶属于科目
科目还没选定,你怎么取课程?



读取数据时把所有的上课形式和对应的科目一次性取出来,这个就不用一次又一次的访问数据库

都读出来,又用不上,不是浪费吗?
如果还要自己缓存起来,不嫌麻烦吗?
缓存到文件和直接访问数据库有什么区别呢?数据表也是文件
缓存到内存,要运行相关服务和加载相应扩展,不一样增加系统开销吗

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