将整个原始文档放在新的属性名称下

Question

我创建了一个聚合管道，它执行以下操作：

1. 转到自定义集合并按_id
查找
2. 转到默认收藏集并按ID查找，将其附加为默认
3. 转到样式集合并按ID查找，将其附加为样式

代码：

Custom.aggregate([{
        $match: {
            '_id': mongoose.Types.ObjectId(req.params.id)
        }
    },
    {
        $lookup: {
            from: 'styles',
            localField: 'styleId',
            foreignField: 'id',
            as: 'style'
        }
    },
    {
        $unwind: '$style'
    },
    {
        $lookup: {
            from: 'default',
            localField: 'styleId',
            foreignField: 'id',
            as: 'default'
        }
    },
    {
        $unwind: '$default'
    },
]).then(docs => res.json(docs))
}

这是当前的输出：

{
    "_id": "597774cc09064e2e4e9fedb7",
    "updatedAt": "2017-07-25T16:41:48.823Z",
    "createdAt": "2017-07-25T16:41:48.823Z",
    "styleId": "401648805",
    "colorId": null,
    "selectedOption": null,
    "deselectedOption": null,
    "currentOptions": [],
    "requiredItems": [],
    "includedItems": [],
    "furtherRemovals": [],
    "furtherAdditions": [],
    "excludedItems": [],
    "name": [],
    "__v": 0,
    "style": {
        "_id": "5902276effabb8bd2926be71",
        "id": "401648805",
        "name": "Luxury 4dr Sedan (2.0L 4cyl Turbo 8A)",
        "createdAt": "2017-07-26T15:28:36.778Z",
        "updatedAt": "2017-07-26T15:49:14.366Z"
    },
    "default": {
        "_id": "5978bfef32d246877e9cb363",
        "updatedAt": "2017-07-26T16:14:39.779Z",
        "createdAt": "2017-07-26T16:14:39.779Z",
        "id": "401648805",
        "requiredItems": [],
        "includedItems": [],
        "furtherRemovals": [],
        "furtherAdditions": [],
        "excludedItems": [],
        "__v": 0
    }
}

我正在尝试将自定义对象包装在“自定义”命名对象中，它更适合我们的数据结构：

{
    "custom": {
        "_id": "597774cc09064e2e4e9fedb7",
        "updatedAt": "2017-07-25T16:41:48.823Z",
        "createdAt": "2017-07-25T16:41:48.823Z",
        "styleId": "401648805",
        "colorId": null,
        "selectedOption": null,
        "deselectedOption": null,
        "currentOptions": [],
        "requiredItems": [],
        "includedItems": [],
        "furtherRemovals": [],
        "furtherAdditions": [],
        "excludedItems": [],
        "name": [],
        "__v": 0,
    },
    "style": {
        "_id": "5902276effabb8bd2926be71",
        "id": "401648805",
        "name": "Luxury 4dr Sedan (2.0L 4cyl Turbo 8A)",
        "createdAt": "2017-07-26T15:28:36.778Z",
        "updatedAt": "2017-07-26T15:49:14.366Z"
    },
    "default": {
        "_id": "5978bfef32d246877e9cb363",
        "updatedAt": "2017-07-26T16:14:39.779Z",
        "createdAt": "2017-07-26T16:14:39.779Z",
        "id": "401648805",
        "requiredItems": [],
        "includedItems": [],
        "furtherRemovals": [],
        "furtherAdditions": [],
        "excludedItems": [],
        "__v": 0
    }
}

我认为它与聚合管道中的$group有关，但我不知道如何构建它。任何帮助将不胜感激 - 对MonogoDB / Mongoose来说相对较新。

Answer 1

在$project之后，我个人$match只需$$ROOT Custom.aggregate([ { $match: { '_id': mongoose.Types.ObjectId(req.params.id) }}, { $project: { _id: 0, custom: '$$ROOT' } }, { $lookup: { from: 'styles', localField: 'custom.styleId', foreignField: 'id', as: 'style' }}, { $unwind: '$style' }, { $lookup: { from: 'default', localField: 'custom.styleId', foreignField: 'id', as: 'default' }}, { $unwind: '$default' } ]).then(docs => res.json(docs)) 新名称“就在管道的开头”：

multiprocessing

自$lookup引入以来，它是所有版本中代码最少且兼容的。

Answer 2

可能有更好的方法，但在管道末端使用$replaceRoot可以获得所需的结构（未经测试）：

Custom.aggregate([{
        $match: {
            '_id': mongoose.Types.ObjectId(req.params.id)
        }
    },
    {
        $lookup: {
            from: 'styles',
            localField: 'styleId',
            foreignField: 'id',
            as: 'style'
        }
    },
    {
        $unwind: '$style'
    },
    {
        $lookup: {
            from: 'default',
            localField: 'styleId',
            foreignField: 'id',
            as: 'default'
        }
    },
    {
        $unwind: '$default'
    },

    {
        $replaceRoot: {
            newRoot: {
                "custom": {
                    "_id": "$_id",
                    "updatedAt": "$updatedAt",
                    "createdAt": "$createdAt",
                    "styleId": "$styleId",
                    "colorId": "$colorId",
                    "selectedOption": "$selectedOption",
                    "deselectedOption": "$deselectedOption",
                    "currentOptions": "$currentOptions",
                    "requiredItems": "$requiredItems",
                    "includedItems": "$includedItems",
                    "furtherRemovals": "$furtherRemovals",
                    "furtherAdditions": "$furtherAdditions",
                    "excludedItems": "$excludedItems",
                    "name": "$name",
                    "__v": "$__v",
                },
                "style": "$style",
                "default": "$default"

            }
        }
    }

]).then(docs => res.json(docs))
}

要使用此功能，您的mongo版本应为3.4或更高。