MongoDB嵌套文档搜索 [英] MongoDB nested documents searching

问题描述

如何搜索文档中嵌套文档的mongodb文档。例如，我有一组私人消息。每条私人消息都有两个嵌套文档 - 一个代表发送用户，另一个代表接收用户。两个嵌套文档都有以下形式 -

How do I search through mongodb documents where documents have nested documents. For example I have a collection of private messages. Each private message has two nested documents - one representing the sending user and the other representing the receiving use. Both nested documents have the form -

userID：34343，
名称：Joe Bloggs

userID: 34343, name: Joe Bloggs

I希望能够搜索用户发送的所有邮件消息（例如，搜索发件人用户嵌套文档）。

I would like to be able to search for all mail messages sent by a user (e.g. search the sender user nested document).

我正在使用java驱动程序。我是否需要创建一个代表嵌套文档的DBObject？

I am using the java driver. Do I need to create a DBObject which represents the nested document?

谢谢

推荐答案

据我所知你有这样的文件结构：

As i understand u have document structure like this:

{
   "someProperty" : 1,
   "sendingUser" : {
               userID : 34343,
               name : "Joe Bloggs"
             },
   "recivingUser" : {
               userID : 34345,
               name : "Joe Bloggs"
             }
}

所以如果你需要找到发送用户ID = 34345的用户你只需要做以下（我只是认为是这样，因为实际上我正在使用c＃driver for mongo）：

So if you need find sending user with userID = 34345 you just need do following(i just think that is so, because actually i am working with c# driver for mongo):

    DBCollection coll = db.getCollection("privateMessages")

    query = new BasicDBObject();

    query.put("sendingUser.userID", new BasicDBObject("$eq", 34345)); 

    cur = coll.find(query); // all documents with  sendingUser.userID = 34345 will be //returned by cursor

同时查看教程 java driver

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