Question

我的申请处理的是包裹和文件之间的多对一的关系。一揽子文件载有多项文件。它们目前存放在邮政总局数据库,使用表 / Pack和文件,表格<编码><>>>>。外国关键栏目<代码>包装-id。

一项新要求要求用户能够重新安排一揽子文件中的文件顺序,因此,我需要开始跟踪。请注意,此类命令不以文件的任何财产为依据,例如日期;该命令可由用户任意指定和重新签署。我需要在各种选择中作出决定。似乎并非难过的是:

Introduce a linking table, with columns package-id, document-id, sequence
Add a column to package to list the order (less change in structure, but now we have relationships pointing in both directions)
Am I missing a better solution?

这必须是一个共同的情景——制定这种方案的标准方式是什么?

Answer 1

As discussed in the comments, only one sort is needed (e.g., the same sort applies to all users).

因此,最容易/最简单的解决办法是修改文件表。

然而,还有多个有待决定的问题。

Does every document in a package need to have a position? (e.g., is the position column NOT NULL)?
- If so, then you ll need to a) go back and update all documents with their positions, and b) modify any things for new documents , old documents and the like to also add the position numbers
- If not, you need to have a clear rule for how to deal with documents without positions e.g., they automatically go to the end of this list. This may be an easier approach than requiring a position.
How to deal with positions no longer being in order e.g., if you have 4 ordered documents, and one is deleted (doc no longer needed), does it work ok with positions (say) 1, 2, 4? Or do you need to re-write them as 1, 2, 3?

最后,有些执行我已做过,分类是一组数据的补充。在这些情况下,我单独提交了一份表格(相当于一揽子补助、文件证明、顺序编号),以留下原始数据。但是,这只是一种分治/主要的解决办法,而不是最简单的解决办法。 (从技术上说,我最简单地忽视和删除,因为别无他用这个新桌。)