How to Query Nested Object in MongoDB

In today’s tutorial, we’ll learn how to query nested objects in MongoDB.

Query Nested Objects in MongoDB

MongoDB offers read operations to retrieve embedded or nested data from a collection or search for embedded or nested documents.

With the help of the db.collection.find() method, we can carry out read operations. This method chooses a document from the collection embedded or nested and then returns the cursor to that document.

Syntax:

>db.collection.find($filter, $projection)

We have two options in the find() method: $filter and $project, briefly described below.

This method returns a cursor to the documents that match the supplied query criteria. The find() method returns the pointer to the documents when you use it since it returns documents when you use it.

You can read more about find() method here. Let’s use the following example to understand the concept:

> db.users.find({address: {country: "United Kingdom"}}).pretty()
> db.users.find({address.country: "United Kingdom"}).pretty()

The sample above code used a pretty technique to locate all of the users who are from the United Kingdom.

The primary difference between these two approaches is that the earlier checks for addresses only include the field { country: ... }, and the latter considers the address.

Other fields in the address or missing from the address have no impact on the country field. For example, you will see the following output after running the above code in MongoShell.

Output:

{ "_id" : ObjectId("54f612b6029b47909a90cesd"), "email" : "johndoe@example.com", "comment" : "This is the first user in the collection.", "country" : "United Kingdom" }