我想以“工厂”管理人员访问的模式。
我有4个制约因素想要执行:
在任何访问中,有一位参加此次访问的管理人员。
manager can visit in the same factory more that one time, but in diffrent days.
管理人员可以在白天访问许多工厂。
一次访问可在工厂进行,最多。
下面表一是:
visit-Factory(Name Factory, date, during, summary)
\where Name Factory, date are PK
visit-manager(Name Factory, data, manager)
\ where Name Factory, date, manager are pk
This enforce the 3 last, but the first is not enforced.
任何想法? 增 编
在良好的数据库设计中,你需要确保数据至少重复。
有鉴于此,审视你目前的设计,看看你可以消除这种重复。
我不知道你们是否了解了各实体以及如何模仿这些实体,但如果是,我想到的是你们所需要的不同实体。
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