How to join two collections in mongoose

Question

I have two Schema defined as below:

var WorksnapsTimeEntry = BaseSchema.extend({
 student: {
     type: Schema.ObjectId,
     ref: \'Student\'
 },
 timeEntries:          


        

Answer 1

As of version 3.2, you can use $lookup in aggregation pipeline to perform left outer join.

Student.aggregate([{
    $lookup: {
        from: "worksnapsTimeEntries", // collection name in db
        localField: "_id",
        foreignField: "student",
        as: "worksnapsTimeEntries"
    }
}]).exec(function(err, students) {
    // students contain WorksnapsTimeEntries
});