如何最好地在mongodb中存储有关继承的信息? [英] How best to store information about inheritance in mongodb?

问题描述

比方说，我有3种类型的对象:Animal，Dog和Poodle.我想将这些对象中的数据作为文档存储在mongodb中.

Let's say I have 3 types of objects: Animal, Dog, and Poodle. I want to store the data in these objects as documents in mongodb.

假设我的Animal文档看起来像:

Let's say my document for Animal looks like:

{
    "name": ...
}

我对Dog的文档如下:

{
    "name": ...,
    "barkFile": ...
}

我的Poodle文档如下:

{
    "name": ...,
    "barkFile": ...,
    "haircut": ...
}

在查找有关存储不同类型对象的建议时，几乎每个人似乎都说使用类型字段.这样对不同类型的动物都适用，就像这样:

When looking up suggestions about storing objects of different types, pretty much everyone seems to say use a type field. That would work fine for different types of animals, like this:

{
    "_type": "cat",
    "name": ...,
    "meowFile": ...
}

{
    "_type": "dog",
    "name": ...,
    "barkFile": ...
}

但是它不允许我存储3个继承级别.基本上我想做这样的事情:

But it doesn't allow me to store 3 levels of inheritance. Basically I want to do something like this:

doc1 = {
    "_type": "animal",
    "name": ...
}

doc2 = {
    "_type": "animal.dog",
    "name": ...,
    "barkFile": ...
}

doc3 = {
    "_type": "animal.dog.poodle",
    "name": ...,
    "barkFile": ...,
    "haircut": ...
}

我不想完全像这样做，因为我希望能够做类似db.animals.find({type: 'animal.dog'})的操作并同时获取doc2和doc3.我宁愿不要重新发明轮子，因此，如果这个问题以前已经解决过(我怀疑已经解决过)，我将不胜感激有人将我引向其他人提出的解决方案.谢谢.

I don't want to do it exactly like this, as I want to be able to do something like db.animals.find({type: 'animal.dog'}) and get both doc2 and doc3. I'd rather not reinvent the wheel, so if this problem has been dealt with before (which I suspect it has), I'd appreciate someone directing me towards the solutions other people have come up with. Thanks.

推荐答案

您可以将类型和子类型简单地存储在这样的数组中:

You could simply store the types and subtypes in an array like this:

doc1 = {
    "_type": ["animal"],
    "name": ...
}

doc2 = {
    "_type": ["animal","dog"],
    "name": ...,
    "barkFile": ...
}

doc3 = {
    "_type": ["animal","dog","poodle"],
    "name": ...,
    "barkFile": ...,
    "haircut": ...
}

使用此模型，查询db.data.find({_type:"dog"})返回doc2和doc3.

Using this model, the query db.data.find({_type:"dog"}) returns both doc2 and doc3.

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