Mongo子字段查询 [英] Mongo Query on Subfields

问题描述

我有一个文档-

  {"_id" : ObjectId("51385d2308d427ce306f0100"),
  "aid" : "1",
  "studyId" : "study-1",
  "mediaType" : "microBlog",
  "text" : "bla bla",
  "sentences" : "bla bla",
  "status" : {
          "algo1" : "required",
          "algo2" : "required",
          "algo3" : "completed",
          "algo4" : "completed"
  },
  "priority" : "u"}

状态字段具有多个具有不同状态值的子字段.是否可以创建查询以返回所有状态"子字段值为必需"的所有文档?

The status field has multiple sub-fields with different status values. Is it possible to create a query such that it returns all documents for which any of the status sub-field's value is "required"?

类似于db.foo.find({status : "required"})的东西，它将为我提供所有子字段具有必需"值的所有文档

Something like db.foo.find({status : "required"}) which would give me all documents for which any of the sub-field has value "required"

推荐答案

另一种更有效的方法是将状态"子文档实现为类型化值"数组，例如:

Another, more efficient, approach would be to implement your "status" sub-document as an array of "typed values", like this:

 {"_id" : ObjectId("51385d2308d427ce306f0100"),
  "aid" : "1",
  "studyId" : "study-1",
  "mediaType" : "microBlog",
  "text" : "bla bla",
  "sentences" : "bla bla",
  "status" : [
          { type: "algo1", value: "required" },
          { type: "algo2", value: "required" },
          { type: "algo3", value: "completed" },
          { type: "algo4", value: "completed" }
  ],
  "priority" : "u"}

使用此查询，您可以找到所有子字段中任何一个字段值为"required"的文档:

This would allow you to find all the documents, for which any of the sub-field has value "required", with this query:

db.foo.find({"status.value":"required"})

在此子字段上定义索引将加快查询速度:

Defining an index on this sub-field would speed up the query:

db.foo.ensureIndex({"status.value":1})

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