twomodelsForCollection.js

var mongoose = require('./../mongoose');
mongoose.connect('localhost', 'testing_twomodelsForCollection');


var schema1 = new mongoose.Schema({
    name: String
}, {collection: 'mystuff'});

var schema2 = new mongoose.Schema({
    age: Number
}, {collection: 'mystuff'});

var A = mongoose.model('A', schema1);
var B = mongoose.model('B', schema2);

mongoose.connection.on('open', function () {

  console.log('creating..');
  A.create({ name: 'first' }, function (err, a) {
    if (err) return console.error(err.stack||err);

    B.findById(a, function (err, b) {
      if (err) console.error(err.stack||err);
      console.error('found an A from B!', b);

      b.age = 45;
      b.save(function (err) {
        if (err) console.error(err.stack||err);
        console.error('saved!');

        A.findById(b, function (err, a) {
          if (err) console.error(err.stack||err);
          console.error('finished', a);

          mongoose.connection.db.dropDatabase(function () {
            mongoose.connection.close();
          });
        });
      });

    });
  })
});

once again! mr heckmann out, to save the world! :) many thanks for this gist! didn't know you could define the collection on the schema regardless of its name.
one thing isn't very clear to me though;
if we find something with A (a.findById) and figure out, that its actually B (based on a type field or such) and we want its model with its virtuals, we call b.findById(a, ...), will Mongoose go back to the server to make an actual query or will it be smart enought to just "rewrap" the result in b?
thanks for making such a great fucking lib!

Calling findById will go back to the server. You might instead try:

A.findById(id, function (er, a) {
  if (a is really b) {
    var b = new B;
    b.init(a._doc);
    // use b normally now
  
I think this works as long as you are not using strict schemas. Can't recall if strict drops unknown paths on the floor (I think so).

Glad Mongoose is working for you :)

okey, I see. Thanks for your answer! Then letting b populate something isn't possible at this point anymore, right?

correct. we'll change this in the future

I figured out, how I could do something in that direction, but I'm not sure how efficient it is. I think I'm now letting mongoose take an additional trip to the mongodb to populate the fileId field, regardless if its set/existent/null;
A.
findById(id).
populate("fileId").
run( function(err, a){
if (a.type==="b"){
var b=new B;
b.init(a._doc);
}
//a would'nt know about the field fileId (and not have it populated)
//b would know about the field fileId and have it populated
})