MongoDB 创建产品摘要集合。

Question

MongoDB 创建产品摘要集合。

6

假设我有这样一个产品集合：

{
"_id": "5a74784a8145fa1368905373",
"name": "This is my first product",
"description": "This is the description of my first product",
"category": "34/73/80",
"condition": "New",
"images": [
    {
        "length": 1000,
        "width": 1000,
        "src": "products/images/firstproduct_image1.jpg"
    },
    ...
],

"attributes": [
    {
        "name": "Material",
        "value": "Synthetic"
    },
    ...
],

"variation": {
    "attributes": [
        {
            "name": "Color",
            "values": ["Black", "White"]
        },
        {
            "name": "Size",
            "values": ["S", "M", "L"]
        }
    ]
}
}

还有像这样的变量集合：

{
"_id": "5a748766f5eef50e10bc98a8",
"name": "color:black,size:s",
"productID": "5a74784a8145fa1368905373",
"condition": "New",
"price": 1000,
"sale": null,
"image": [
    {
        "length": 1000,
        "width": 1000,
        "src": "products/images/firstvariation_image1.jpg"
    }
],
"attributes": [
    {
        "name": "Color",
        "value": "Black"
    },
    {
        "name": "Size",
        "value": "S"
    }
]
}

我希望将文档分开存储，为了方便浏览、搜索和使用faceted搜索，我想在单个查询中获取所有数据，但是我不想在我的应用程序代码中进行连接操作。我知道可以通过创建第三个名为summary的集合来实现这一目标，它可能长这样:

{
"_id": "5a74875fa1368905373",
"name": "This is my first product",
"category": "34/73/80",
"condition": "New",
"price": 1000,
"sale": null,
"description": "This is the description of my first product",
"images": [
    {
        "length": 1000,
        "width": 1000,
        "src": "products/images/firstproduct_image1.jpg"
    },
    ...
],

"attributes": [
    {
        "name": "Material",
        "value": "Synthetic"
    },
    ...
],

"variations": [
    {
        "condition": "New",
        "price": 1000,
        "sale": null,
        "image": [
            {
                "length": 1000,
                "width": 1000,
                "src": "products/images/firstvariation_image.jpg"
            }
        ],
        "attributes": [
            "color=black",
            "size=s"
        ]
    },
    ...
]
}

问题是，我不知道如何让摘要集合与产品和变体集合保持同步。我知道可以使用mongo-connector实现，但我不确定如何实施。请帮助我，我还是一个初学者程序员。

- s.frz

1个回答

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- Saravana · Answer 1

实际上，您不需要维护一个摘要集合，将产品和变体摘要存储在另一个集合中是多余的。

相反，您可以使用聚合管道$lookup来使用productID外连接产品和变体

聚合管道

db.products.aggregate(
    [
        {
            $lookup : {
                from : "variation",
                localField : "_id",
                foreignField : "productID",
                as : "variations"
            }
        }
    ]
).pretty()