Mongoose Populate Method is not populating value - node.js

Question

I have two mongoose schema as following
var ServiceSubType = new Schema({
displaySubTypeName : String,
subTypeDescription : String,
status : { type: String, default: Constants.ACTIVE },
lastUpdatedOn : Date,
createdOn : { type: Date, default: Date.now }
} , { collection: 'SERVICE_SUB_TYPES' });
and
var ServiceType = new Schema({
displayName : String,
description : String,
status : { type: String, default: Constants.ACTIVE },
lastUpdatedOn : Date,
serviceSubTypeId : {type: Schema.Types.ObjectId, ref: 'ServiceSubType', index: true},
createdBy : { type: Schema.Types.ObjectId, ref: 'SystemUser', index: true },
createdOn : { type: Date, default: Date.now }
} , { collection: 'SERVICE_TYPES' });
I have populated Type Object as below
module.exports.addNewServiceType = function(serviceType_obj, callback) {
serviceType_obj.save(serviceType_obj,callback);
}
Now I am trying to populate ServiceSubType document and then at the same time trying to populate "serviceSubTypeId" of ServiceType object referenced to ServiceSubType created.
Here is my piece of code for the same purpose.
module.exports.addServiceSubType = function(serviceTypeObjId, serviceSubType_obj, callback) {
serviceSubType_obj.save(serviceSubType_obj, function (error, serviceSubType) {
});
serviceSchema.ServiceType.findById(serviceTypeObjId, function (err, serviceType) {
var opts = { path: 'serviceSubTypeId'};
serviceSchema.ServiceType.populate(serviceType, opts, function (err, user) {
console.log(serviceType);
});
}).exec(callback);
}
But it is not workign and not populating any value in Existing SubType object.
I admit my approach could be very wrong as I am very new in this technology. Appreciate any kind of help to run this piece of code as expected.
Thanks
Ajoy

Answer 1

I think your ref should be the same setting as the collection on the object
serviceSubTypeId : {
type: Schema.Types.ObjectId,
ref: 'SERVICE_SUB_TYPES', <==== your collection type goes here
index: true
},
Mongoose doesn't know anything about your JavaScript object types. Instead, it tracks things based on the collection name that you provide (or that it generates).
update based on comments below
I have some example code that I wrote a while back, and it looks like I'm letting Mongoose generate the collection name for me. However, I am supplying a name to the mogoose.model() call, when registering my type for a collection.
For example, I have a Post type and a User type. The Post contains an author which is a reference to the User.
It looks like this:
// post
// ----
var PostSchema = new mongoose.Schema({
date: {type: Date, required: true, default: Date.now},
title: {type: String, required: true},
content: {type: String, required: true},
author: {
type: SchemaTypes.ObjectId,
ref: "user"
},
comments: [CommentSchema]
});
var Post = mongoose.model("blog", PostSchema);
// user
// ----
var UserSchema = mongoose.Schema({
firstName: {type: String},
lastName: {type: String},
username: {type: String, required: true, index: {unique: true}},
email: {type: String, required: true},
password: {type: String, required: true},
url: {
type: mongoose.Schema.Types.ObjectId,
ref: "url"
}
});
User = mongoose.model("user", UserSchema);
In this example code, I'm setting the ref to "user" because I am registering my model as "user" down below, in the mongoose.model method call.
Are you registering your models using mongoose.model and supplying a name? if so, use that name.