mongoose-paginate sorting by referenced document

Question

I would like to sort my Group-Model by the name of the departure_country with mongoose-paginate and NodeJS.

My Group-Schema:

  var GroupSchema = new Schema({
        name: String,
        flight_date: Date,
        ....
        departure_country: {type: Schema.ObjectId, ref: 'Country'},
        ....
  });

The Country-Schema:

 var CountrySchema = new Schema({
     name: String,
     code: String,
 });

Using the sortBy-option of mongoose-paginate sorts by the country's _ids and I don't know how to tell it to sort by the name.

But in fact I don't think that would be possible as it's a populated field and 'joining' is done in the app level, not mongoose level. You could include country name in your `GroupSchema` and sort by it — Vsevolod Goloviznin, Oct 13 '15 at 19:04
Of course :) did not work. Neither did `{"departure_country": {"name": -1}}` — molerat, Oct 13 '15 at 19:04
Why can't you include country name in the `GroupSchema`? See my previous comment. — Vsevolod Goloviznin, Oct 13 '15 at 19:06
Sometimes you don´t want to sort by the county name but maybe by the country code. Including that field as a non-referenced field does not seem very nice to me. — molerat, Oct 13 '15 at 19:08
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/92183/discussion-between-molerat-and-vsevolod-goloviznin). — molerat, Oct 13 '15 at 19:14
Possible duplicate of [Node - Mongoose 3.6 - Sort query with populated field](http://stackoverflow.com/q/19428471/1202461). — Leonid Beschastny, Oct 13 '15 at 19:57
I see, you are right and Vsevolod also told me the same thing — molerat, Oct 13 '15 at 20:00
{"departure_country.name": -1} - this will work with only nested documents, not references — igorpavlov, Oct 19 '15 at 22:24

score 0 · Answer 1 · answered Oct 19 '15 at 18:22

0

how about making the country code the _id of Country-Schema?

then departure_country: {type: String, ref: 'Country'}

That might actually be a better design. Country-Schemas _id would be small, and country codes shouldn't have collisions. Also in GroupSchema you'd use less space to store the "foreign key" departure_country.

then you'd be able to sort by departure_country and there's a chance the sort would also be valid for country name.

answered Oct 19 '15 at 18:22

kio

374
1
10

sometimes I need to display or even sort by the name of the country as well – molerat Oct 20 '15 at 11:02
@molerat don't think there's a way to do that since you're populating. you'd have to do that on the nodejs side. http://underscorejs.org has good functions for that. sortBy or even groupBy could be useful. – kio Oct 20 '15 at 17:00
If you get 50 of 10000 entries and sort those only, you will not have the same result as if sorting 10000 and then picking 50. – molerat Oct 20 '15 at 17:09
it's a consequence of data normalization in mongo. back to what I suggested, I think it can even work if you use the country name as an id. provided you have a pre-defined set of countries - so they're not user input (if they are user input, you need a way to normalize the name string to avoid duplicates). You could also make departure country an object and have both the id and the country name in there. – kio Oct 20 '15 at 17:46

mongoose-paginate sorting by referenced document

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