javascript - 如何在 Mongoose 中检索子文档

Question

我的数据库中有 mongo 集合:

[
    {
        "_id": "59955bb0cd522a00bcaab08c",
        "lang": "en",
        "__v": 0,
        "message_subsets": [
            {
                "identifier": "errors",
                "_id": "59955bb0cd522a00bcaab08d",
                "messages": [
                    {
                        "identifier": "invalid",
                        "message_text": "$FIELD$ is invalid",
                        "_id": "59955bb0cd522a00bcaab091"
                    },
                    {
                        "identifier": "empty",
                        "message_text": "$FIELD$ is required",
                        "_id": "59955bb0cd522a00bcaab090"
                    }
                ]
            }
        ]
    },
    {
        "_id": "59955bb0cd522a00bcaab08c",
        "lang": "ru",
    ...
]

它是由 Mongoose 模式构建的:

const MessageSchema = new mongoose.Schema({
    identifier: {
        type: String,
        unique: true,
        required: true,
        trim: true
    },
    message_text: {
        type: String,
        required: true,
        trim: true
    }
});

const MessageSubsetSchema = new mongoose.Schema({
    identifier: {
        type: String,
        unique: true,
        required: true,
        trim: true
    },
    messages: [MessageSchema]
});

const LangMessageSetSchema = new mongoose.Schema({
    lang: {
        type: String,
        unique: true,
        required: true,
        trim: true
    },
    message_subsets: [MessageSubsetSchema]
});

我想从 message_subsets 数组项中检索所有具有 "identifier": "errors" 的 messages(如果其父项具有 "lang": "en")。 因为我对 mongoose 和 mongo 有点陌生，所以我坚持了下来!您能帮助我以正确的方式进行数据查询吗？谢谢。

Answer 1

这应该有效:

Collection.find({'messages.message_subsets.identifier':'errors', 'lang': 'en'}, {'messages': 1})