Mongoose: multiple query populate in a single call

Question

In Mongoose, I can use a query populate to populate additional fields after a query. I can also populate multiple paths, such as

Person.find({})
 .populate('books movie', 'title pages director')
 .exec()

However, this would generate a lookup on book gathering the fields for title, pages and director - and also a lookup on movie gathering the fields for title, pages and director as well. What I want is to get title and pages from books only, and director from movie. I could do something like this:

Person.find({})
 .populate('books', 'title pages')
 .populate('movie', 'director')
 .exec()

which gives me the expected result and queries.

But is there any way to have the behavior of the second snippet using a similar "single line" syntax like the first snippet? The reason for that, is that I want to programmatically determine the arguments for the populate function and feed it in. I cannot do that for multiple populate calls.

royhowie · Accepted Answer · 2015-06-13 06:06:52Z

155

After looking into the sourcecode of mongoose, I solved this with:

var populateQuery = [{path:'books', select:'title pages'}, {path:'movie', select:'director'}];

Person.find({})
 .populate(populateQuery)
 .execPopulate()

edited Jun 13, 2015 at 6:06

royhowie

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answered Jan 13, 2014 at 19:53

Se7enDays

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5 Comments

scaryguy Over a year ago

Does this kind of usage has any performance impacts against chaining multiple populates?

Akos K Over a year ago

@GoncharDenys no, it fails with .populate(...).exec is not a function

Anshuman Pattnaik Over a year ago

execPopulate is not a function , please help

Hamza Hmem Over a year ago

@AkosK @Anshuman Pattnaik just remove the .execPopulate() it will work properly

Hamza Hmem Over a year ago

@scaryguy yes there are some impacts on performance :/ , but unfortunately there are some cases we are imposed to make multiple chaining populates... please if you have any suggestions let us know

Ivan · Accepted Answer · 2017-08-29 14:40:06Z

17

you can also do something like below:

{path:'user',select:['key1','key2']}

edited Aug 29, 2017 at 14:40

Ivan

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answered Aug 29, 2017 at 13:48

Kartik Garasia

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Comments

Rustamjon Kirgizbaev · Accepted Answer · 2020-10-26 09:12:46Z

5

You achieve that by simply passing object or array of objects to populate() method.

const query = [
    {
        path:'books', 
        select:'title pages'
    }, 
    {
        path:'movie', 
        select:'director'
    }
];
const result = await Person.find().populate(query).lean();

Consider that lean() method is optional, it just returns raw json rather than mongoose object and makes code execution a little bit faster! Don't forget to make your function (callback) async!

answered Oct 26, 2020 at 9:12

Rustamjon Kirgizbaev

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Comments

Youness zagouri · Accepted Answer · 2023-10-19 10:44:50Z

3

const order = await orderModel.findOne({ _id : id }).populate([
    {path : 'company_id' , select : ['companyName']} , 
    {path : 'customer_id' , select : ['first_name' , 'family_name' , 'email']}
]);

answered Oct 19, 2023 at 10:44

Youness zagouri

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Comments

Lawrence Edmondson · Accepted Answer · 2018-01-27 06:47:07Z

1

This is how it's done based on the Mongoose JS documentation http://mongoosejs.com/docs/populate.html

Let's say you have a BookCollection schema which contains users and books In order to perform a query and get all the BookCollections with its related users and books you would do this

models.BookCollection
    .find({})
    .populate('user')
    .populate('books')
    .lean()
    .exec(function (err, bookcollection) {
    if (err) return console.error(err);
    try {
        mongoose.connection.close();
        res.render('viewbookcollection', { content: bookcollection});

    } catch (e) {
        console.log("errror getting bookcollection"+e);
    }

answered Jan 27, 2018 at 6:47

Lawrence Edmondson

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2 Comments

Jacob Over a year ago

They wanted to select certain data from each one of those paths. Like the book's path they only wanted to populate the title and pages. This would populate the whole model for users and books.

Jacob Over a year ago

Its seems the author of the question solved it themselves anyways.

Pankaj Singh · Accepted Answer · 2023-01-06 10:20:55Z

1

//Your Schema must include path

let createdData =Person.create(dataYouWant)


await createdData.populate([{path:'books', select:'title pages'},{path:'movie', select:'director'}])

edited Jan 6, 2023 at 10:20

answered Jan 6, 2023 at 9:58

Pankaj Singh

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