并发更新到相同的集合相同的文档 [英] Concurrent update to the same collection same document

问题描述

问题陈述

如何处理同一集合和同一文档上的并发更新命令.

How do i handle concurrent update commands on same collection and same document.

当前数据库结构

编辑-结构已更改

  {
     "userId":1,
     "summary_extra":[
        {
           "some_id":1,
           "names":[
              "one",
              "two"
           ]
        },
        {
           "some_id":2,
           "names":[
              "three",
              "four"
           ]
        }
     ]
  },
  {
     "userId":2,
     "summary_extra":[
        {
           "some_id":1,
           "names":[
              "one",
              "two"
           ]
        },
        {
           "some_id":2,
           "names":[
              "three",
              "four"
           ]
        }
     ]
  }

如果一个用户一次尝试更新，则更新文档不会有任何问题.但是，如果有多个用户(可能至少有10个用户)，那么我该如何更新同一文档.

If one user tries to update at a time then there wont be any problem to update the document. But if there are more than one users(whihc is likely to 10, minimum) then how can i update same document.

在这种情况下我该怎么办?

What do i do in this scenarios??

N:B数据精确，但结构却完全相同.

N:B Datas are exact, but exact same structure i have.

编辑:现在，我认为我可以由多个用户同时更新同一集合中的两个不同文档?

EDIT : So now i think i can update two different documents in the same collections simultaneously by multiple users??

推荐答案

您可以包括一个version字段，该字段随每次更新而递增(在您的更新和查询过滤器中，将增加一个$ inc).然后，如果有人从您拥有的版本中更新了文档，则无法进行任何更新.如果您使用的是Morphia，则@Version注释会为您透明地进行处理.

You can include a version field which gets incremented with each update (it'd be one more $inc in your update and a query filter). Then if someone has updated the document away from the version you have, no updates can go through. If you're using Morphia, the @Version annotation takes care of this for you transparently.

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