Node js mongodb模块嵌入式文档

Question

I am using node module "mongodb" and just started with the schema architecture for it. I read the documentation of mongodb module and found that there is no way I can store reference to another document inside a document. I want to achieve something like below:

DocumentA
{
_id: ObjectID(123456789),
fieldA1: "test",
fieldA2: "test",
DocumentB: <ObjectId>
}

DocumentB
{
_id: ObjectID(09876543),
fieldB1: "test2",
fieldB2: "test2"
}

I want to query DocumentA by ObjectID(123456789) and fetch DocumentB also so that I can access the value if "fieldB2" & "fieldB1". Is this possible to do in node js mongodb? If yes then please give me some knowledge or give me another solution(like, is querying twice for fetching inner object ok?)

Answer 1

Mongo does support the concept of references , but they are very weak references. There is no constraints on what your reference may be, so it may be totally invalid.

I think that there are 2 concepts that you're missing:

1. Mongo does not have the concept of 'joins'. Its just not in their paradigm.
2. Instead Mongo favors embedding documents. So in your case, instead of having 2 documents, you can just have

.

DocumentA
{
_id: ObjectID(123456789),
fieldA1: "test",
fieldA2: "test",
DocumentB: {
    fieldB1: "test2",
    fieldB2: "test2"
    }
}

You can then just query for Document A and do whatever combinatoric logic you want with Document B because its right there with Document A