Yazılım IO Yazılım IO - 1 year ago 457
Node.js Question

Mongoose Inner Join

user collection

user : {
"_id" : md5random,
"nickname" : "j1",
"name" : "jany"
user : {
"_id" : md5random,
"nickname" : "j2",
"name" : "jenneffer"

friendship collection

friendship : {
"_id" : md5rand,
"nick1" : "j1",
"nick2" : "j2",
"adTime" : date

for example SQL

SELECT friendship.adTime, user.name
FROM friendship
(user.nickname=friendship.nick1 or user.nickname=friendship.nick2)

Is there any way in the MONGO to get this SQL result?

I WANT GET RESULTS, i know mongo not supporting this request.
But what is this better solution? Any body can write an exeample for me?

Answer Source

MongoDB is n document-oriented, not a relational database. So it doesn't have a query language like sql. Therefore you should change you database schema.

Here is a example:

  1. Define your schema. You can't save relations in mongodb like in sql databases. so add the friends directly to the user. to add attributes to these relations you have to create a new model (here: Friend).

    var userSchema = mongoose.Schema({
        nickname: String,
        name: String,
        friends: [{type: mongoose.Schema.Types.ObjectId, ref: 'Friend'}]
    var friendSchema = mongoose.Schema({
        user: {type: mongoose.Schema.Types.ObjectId, ref: 'User'},
        addTime: Date
    var User = mongoose.Model('User', userSchema);
    var Friend = mongoose.Model('Friend', friendSchema);

Your query to get all addTimes's could look like this:

User.find().populate('friends').exec(function(err, users) {
    if (err) throw err;

    var adTimes = [];
    users.forEach(function(user) {
        user.friends.forEach(function(friend) {

    response.send(adTimes); // adTimes should contain all addTimes from his friends

NOTE: The above schema should work, but maybe you should use a relational (like MySQL) or graph database (like Neo4j) instead of a document-oriented like MongoDB.

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