MongoDB 查询帮助 - 查询子对象中任意键的值 [英] MongoDB Query Help - query on values of any key in a sub-object

问题描述

我想对该集合执行查询，以确定哪些文档在与某个值匹配的事物中具有任何键.这可能吗?

I want to perform a query on this collection to determine which documents have any keys in things that match a certain value. Is this possible?

我有一组文档，例如:

{
    "things": {
        "thing1": "red",
        "thing2": "blue",
        "thing3": "green"
    }
}

为了简洁

推荐答案

我建议更改架构，以便您可以在 MongoDB 中实际进行合理的查询.

I'd suggest a schema change so that you can actually do reasonable queries in MongoDB.

来自:

{
    "userId": "12347",
    "settings": {
        "SettingA": "blue",
        "SettingB": "blue",
        "SettingC": "green"
    }
}

到:

{
    "userId": "12347",
    "settings": [
        { name: "SettingA", value: "blue" },
        { name: "SettingB", value: "blue" },
        { name: "SettingC", value: "green" }
    ]    
}

然后，您可以对 "settings.value" 进行索引，并执行如下查询:

Then, you could index on "settings.value", and do a query like:

db.settings.ensureIndex({ "settings.value" : 1})

db.settings.find({ "settings.value" : "blue" })

更改确实很简单...，因为它将设置名称和设置值移动到完全可索引的字段，并将设置列表存储为数组.

The change really is simple ..., as it moves the setting name and setting value to fully indexable fields, and stores the list of settings as an array.

如果您无法更改架构，您可以尝试 @JohnnyHK 的 解决方案，但请注意，就性能而言，这基本上是最坏的情况，并且无法有效地使用索引.

If you can't change the schema, you could try @JohnnyHK's solution, but be warned that it's basically worst case in terms of performance and it won't work effectively with indexes.

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