mongodb - How to use a field other than the primary key _id to perform a related query?

Question

Now there is an article post model that uses cateId to associate with the Category category. But cateId is not _id. Resulting in an error when retrieving.
Can we only associate through _id? How to use non-_id under Category to associate?

var PostSchema = new mongoose.Schema({
    author: { type: mongoose.Schema.Types.ObjectId},
    title: String,
    content: String,
    imgUrl: String,
    pv: { type:Number, default:0}, 
    like: { type:Number, default:0}, 
    keep:  { type:Number, default:0}, 
    comments: { type:Number, default:0}, 
    cateId: { type:Number, ref:'Category'},
    type:  Number,
    create_date: { type: Date, default: Date.now }
},{
    versionKey: false 
})

var Post = mongoose.model('Post', PostSchema)

Answer 1

1, Mongoose’s populate can only be on _id;

2. Therefore, you can only write your own code for association here. First query one collection, then query another collection, and associate it yourself.

For reference.

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