How to Get the id of Inserted Document in MongoDB in NodeJS

MongoDB is a popular type of NoSQL database. It stores data in documents that look like JSON. When working with MongoDB using Mongoose, _id is a unique identifier of each document in a collection and it can be used to perform operations on the document, such as updating or deleting it. The insertion method is used to insert a document into a MongoDB collection.

In this article, We will learn about the process of Getting the _id of the inserted document in Mongo database in NodeJS by understanding the various methods along with the examples and so on.

How to get the ID of the Inserted Document?

When working with MongoDB and Mongoose developers often need to perform tasks such as updating documents, Inserting documents, and executing complex queries. The below methods help us to understand How to get the ID of the Inserted Document are as follow:

1. Using insertOne() Method with insertedId Property
2. Using insertOne() Method with ops Property

Steps to Create Database Connection and Mongoose Schema

Step 1: Install Necessary Dependencies

npm install mongoose express

Step 2: Create the MongoDB connection

Create a dbConnect.js file and paste the below code

const mongoose = require("mongoose");

mongoose
  .connect("mongodb://localhost:27017/gfg")
  .then(() => {
    console.log("Connected to MongoDB database successfully!");
  })
  .catch((err) => {
    console.error("Error connecting to MongoDB:", err);
  });

Step 3: Create a Mongoose Schema

Create a model.js file, which includes the Mongo schema [courseSchema] with fields like Title, Fees, Instructor & Date.

const mongoose = require("mongoose");

const courseSchema = new mongoose.Schema({
  Title: {
    type: String,
  },
  Fees: {
    type: Number,
  },
  Instructor: {
    type: String,
  },
  date: Date,
});

const Course = mongoose.model("Course", courseSchema);

module.exports = Course;

1. Using insertOne() Method with insertedId Property

In the MongoDB, insertOne() method is used to insert a single document into the collection. It also returns the document that contains inserted document details & inserted Id property.

Syntax:

db.collection.insertOne(document, callback)

• document: The document to be inserted into the collection.
• callback: An optional callback function that is called after the insertion is complete

Example 1: Adding the Java course and getting the Inserted Id

const mongoose = require("mongoose");
const Course = require("./model");
const db = require("./dbConnect");

async function insertData() {
  try {
    
    const javaCourse = new Course({
      Title: "Java",
      Fees: 10000,
      Instructor: "Akhil Sir",
      date: new Date("2024-03-23"),
    });

    
    const savedCourse = await javaCourse.save();

    
    const insertedId = savedCourse._id;
    console.log("Inserted document _id:", insertedId);

    console.log("Data inserted successfully");

    
    const insertedData = await Course.find({});
    console.log("Inserted data:");
    console.log(insertedData);
  } catch (error) {
    console.error("Error inserting data:", error);
  } finally {
    
    mongoose.disconnect();
  }
}


insertData();

Output:

Server is running on port 3000
MongoDB connected
Inserted document _id: new ObjectId('662894fbef2273c58f5d1592')
Data inserted successfully
Inserted data:
[
  {
    _id: new ObjectId('662894fbef2273c58f5d1592'),
    Title: 'Python',
    Fees: 25000,
    Instructor: 'Sushant Sir',
    date: 2024-03-23T00:00:00.000Z,
    __v: 0
  }
]

Example 2: Adding the Python course & getting the Inserted Id

const mongoose = require("mongoose");
const Course = require("./model");
const db = require("./dbConnect");

async function insertData() {
  try {
    const pythonCourse = new Course({
      Title: "Python",
      Fees: 25000,
      Instructor: "Sushant Sir",
      date: new Date("2024-03-23"),
    });

  
    const savedCourse = await pythonCourse.save();

   
    const insertedId = savedCourse._id;
    console.log("Inserted document _id:", insertedId);

    console.log("Data inserted successfully");

    
    const insertedData = await Course.find({});
    console.log("Inserted data:");
    console.log(insertedData);
  } catch (error) {
    console.error("Error inserting data:", error);
  } finally {
   
    mongoose.disconnect();
  }
}

insertData();

Output:

Server is running on port 3000
MongoDB connected
Inserted document _id: new ObjectId('662894c857ef020ca85343f0')
Data inserted successfully
Inserted data:
[
  {
    _id: new ObjectId('662894c857ef020ca85343f0'),
    Title: 'Python',
    Fees: 25000,
    Instructor: 'Sushant Sir',
    date: 2024-03-23T00:00:00.000Z,
    __v: 0
  }
]

2. Using the insertOne() method with the ops property

In the MongoDB, insertOne() returns a result object that contains an ops property, which is an array of documents that were inserted and the ops property contains the full document or documents that were inserted into the collection.

Syntax:

db.collection.insertOne(document, callback)

• document: The document to be inserted into the collection.
• callback: An optional callback function that is called after the insertion is complete
• The ops field is not directly used in above examples. In some cases, the ops field in the result object may contain an array of inserted documents.

Example 1: Adding the Java course and getting the Inserted Id

const mongoose = require("mongoose");
const Course = require("./model");
const db = require("./dbConnect");

async function insertData() {
  try {
    
    const courseObject = {
      Title: "Java",
      Fees: 10000,
      Instructor: "Akhil Sir",
      date: new Date("2024-03-23"),
    };

    
    const result = await Course.collection.insertOne(courseObject);
    if (result && result.acknowledged && result.insertedId) {
     
      const insertedId = result.insertedId;
      console.log("Inserted document _id:", insertedId);
    } else {
      throw new Error(
        "Failed to insert document or inserted document is empty."
      );
    }

    console.log("Data inserted successfully");

  
    const insertedData = await Course.find({});
    console.log("Inserted data:");
    console.log(insertedData);
  } catch (error) {
    console.error("Error inserting data:", error);
  } finally {
   
    mongoose.disconnect();
  }
}


insertData();

Output:

Server is running on port 3000
MongoDB connected
Inserted document _id: new ObjectId('66289473049ee4bee5048def')
Data inserted successfully
Inserted data:
[
  {
    _id: new ObjectId('66289473049ee4bee5048def'),
    Title: 'Java',
    Fees: 10000,
    Instructor: 'Akhil Sir',
    date: 2024-03-23T00:00:00.000Z
  }
]

Example 2: Adding the Python course and getting the Inserted Id

const mongoose = require("mongoose");
const Course = require("./model");
const db = require("./dbConnect");

async function insertData() {
  try {
    const courseObject = {
      Title: "Python",
      Fees: 15000,
      Instructor: "Nikhil Sir",
      date: new Date("2024-03-23"),
    };

    const result = await Course.collection.insertOne(courseObject);

    if (result && result.acknowledged && result.insertedId) {
      const insertedId = result.insertedId;
      console.log("Inserted document _id:", insertedId);
    } else {
      throw new Error(
        "Failed to insert document or inserted document is empty."
      );
    }

    console.log("Data inserted successfully");

   
    const insertedData = await Course.find({});
    console.log("Inserted data:");
    console.log(insertedData);
  } catch (error) {
    console.error("Error inserting data:", error);
  } finally {
    
    mongoose.disconnect();
  }
}

insertData();

Output:

Server is running on port 3000
MongoDB connected
Inserted document _id: new ObjectId('66289434eec367e5b13ef946')
Data inserted successfully
Inserted data:
[
  {
    _id: new ObjectId('66289434eec367e5b13ef946'),
    Title: 'Python',
    Fees: 15000,
    Instructor: 'Nikhil Sir',
    date: 2024-03-23T00:00:00.000Z
  }
]

Conclusion

Overall summary, In the above approaches we are using the insertOne with ops property & insertedId property to insert the document in MongoDb collection. and result from these methods contains information of inserted documents with id. so we can easily access the insertedId property using _id ,and the ops array. The above approachs allows developer to easily obtain the unique identifier(s) assigned by MongoDB to the newly inserted documents, which can be useful for various purposes, such as referencing or updating the documents later on.