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The following article provides an overview of MongoDB find by Id() method. MongoDB provides a find by Id() function which can retrieve documents matching a user id.

To use search by Id() in MongoDB, you need to use the find() function. If no document matching the specified ID is found, a null value is returned.

It is one of the basic functions which is widely used when there is a need to retrieve a document based on its id.

MongoDB finds the id() function

The user will use the find() function to lookup using id() in MongoDB. Following is the syntax to use the find by id() function in MongoDB database.

db.collection_name.find(query, projection)

1. query − This is an optional parameter. It uses query operators to specify the selection filter.

   If this parameter is omitted, all documents in the collection will be returned.

2. projection - This is also an optional parameter. It provides the fields that are returned if the query filters are satisfied.

   If this option is omitted, all fields in matching documents will be returned.

3. Return Type − Returns a cursor to the documents matching the search criteria.

find by id()Retrieves the details of a document matching a specific id specified by the user, where id is an id that is automatically generated when a document is created in the database, as the name suggests.

Again, _idthe parameter is the id that is automatically generated when the document is put into the database.

A simple find() function will be used without specifying any conditions to access the automatically generated ID. In Mongosh, db.collection_name.find()the function will automatically iterate the cursor and display the first 20 documents of the collection.

Different languages ​​use different ways to retrieve or find a document by specifying its id.

MongoDB example of looking up by id()

Below are some examples showing id()the use of lookups in a MongoDB database. In addition, there is a collection in the database called teams, which will be used in all examples in this article.

db={
  "teams": [
    {
      team: "Manchester City ",
      position: "1st",
      points: 70
    },
    {
      team: "Liverpool",
      position: "2nd",
      points: 69
    },
    {
      team: "Chelsea",
      position: "3rd",
      points: 59
    },
    {
      team: "Arsenal",
      position: "4th",
      points: 54
    },
    {
      team: "Tottenham",
      position: "5th",
      points: 51
    },
    {
      team: "Manchester United",
      position: "6th",
      points: 50
    }

  ]
}

In this example, you will use the find() function without any parameters. Given below is the code for this query.

db.teams.find();

The output screenshot of the above query is as follows.

In the example given above, find()the find() function of MongoDB is used without passing any parameters. Since no parameters are passed, the find() function will retrieve all the detail documents present in the collection.

ObjectId()Furthermore, we can see that an additional field is automatically inserted at the beginning of each document .

MongoDB inserts this for each new document inserted by the user ObjectId(). This ObjectId()is unique and cannot be used in multiple documents.

ObjectId()This is one of the easiest ways to get all the documents and use them according to your specific requirements.

Searching in MongoDB using the ObjectId() method

You will use the find() function and pass it the ObjectId() parameter.

The code for this query is given below.

db.teams.find({
  _id: ObjectId("5a934e000102030405000002")
})

The output screenshot of the above query is as follows.

In the above example, the document is ObjectId()found based on the document's id. ObjectId()id is a unique ID that is automatically assigned when a new document is inserted into a collection.

In MongoDB, you can ObjectId()pass parameters to find()the function and the user will see the corresponding document on the console.

Find by name method in MongoDB

You will use the function by passing the parameter of the field instead of a unique ObjectId find().

The code for this query is given below.

db.teams.find({
  "team": "Arsenal"
})

The output screenshot of the above query is as follows.

As we have seen in the example given above, users can also find()pass in arguments to the function for other fields of the document.

Since team is also a field that can be used to filter each document, documents for teams like Arsenal are found and all their details are displayed to the user on the console.

This MongoDB article describes the find by Id() function and how it can be used to retrieve a document based on a user-specified id in MongoDB.

As we all know, find()method is used to retrieve a document based on the provided id. Internally, find()the method calls findOne()to handle this case.