没有字段名称的mongodb查询 [英] mongodb query without field name

问题描述

我想查询所有具有包含特定值的字段的对象.例如，我有两个文档:

I would like query all objects that have a field containing a specific value. For example, I have two documents:

{"123": "apple", "217": "pear", "179": "orange"}
{"831": "pear", "189": "grapes"}

，并希望获取具有值为"apple"的字段的所有对象，但我不知道该字段的名称.是否可以在MongoDB中指定查询来实现此目的? (对象中的数字键是子代id，而对象中的值是长GUID)

and would like to get all objects that has a field whose value is "apple", but I do not know the name of the field. Is it possible to specify a query in MongoDB to achieve this? (The numerical keys in the objects are children ids, and the values in the objects are long GUIDs)

推荐答案

不幸的是，MongoDB不支持任何查询具有特定值的所有字段的方法.现有的Jira票证要求进行此增强: https://jira.mongodb.org/browse/SERVER -1248 .随意发表评论，投票或关注该票证.

Unfortunately, MongoDB does not support any method of querying all fields with a particular value. There is an existing Jira ticket requesting this enhancement: https://jira.mongodb.org/browse/SERVER-1248 . Feel free to comment, vote, or follow that ticket.

同时，处理此问题的通常方法是更改​​MongoDB模式.对于您的示例，您将更改现有架构:

In the meantime, the usual way that this is handled is to change the MongoDB schema. For your example, you would change your existing schema:

{"123": "apple", "217": "pear", "179": "orange"} 
{"831": "pear", "189": "grapes"} 

您可能会像这样构造它:

And you might structure it something like this:

 { tags: [
        { cid: "123", value: "apple" },
        { cid: "217", value: "pear" },
        { cid: "179", value: "orange" },
      ]
    }
   { tags: [
        { cid: "831", value: "pear" },
        { cid: "189", value: "grapes" },
      ]
    }

完成此操作后，您可以执行以下查询以查找所有所需文档:

Once you've done this, you can perform the follwing query to find all of the desired documents:

 db.docs.find( {'tags.value': "apple" } )

请注意，该架构允许您索引'tags.cid'和'tags.value'字段，而原始架构则没有.

Note that this schema allows you to index the 'tags.cid' and 'tags.value' fields, which your original schema does not.

我希望这会有所帮助.

-威廉

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