MongoDB CRUD Operations Complete Beginner Guide

Learn Create, Read, Update, and Delete operations in MongoDB with easy examples, practice questions, and MCQs.

MongoDB CRUD Operations are the basic operations used to manage data inside a MongoDB database. CRUD is one of the most important topics for beginners who are learning MongoDB, backend development, or MERN Stack development.

What is CRUD in MongoDB?

CRUD stands for:

CRUD operations are used to insert, read, update, and delete data from a database. Almost every website and application uses CRUD operations.

Create Operation in MongoDB

Create operation is used to insert new documents into a MongoDB collection.

• insertOne()
• insertMany()

Insert One Document

db.students.insertOne({
   name: "Harsh",
   age: 21,
   course: "BCA",
   marks: 85
})

Insert Multiple Documents

db.students.insertMany([
   {
      name: "Rahul",
      age: 20,
      course: "BCA",
      marks: 75
   },
   {
      name: "Aman",
      age: 22,
      course: "BTech",
      marks: 90
   }
])

Read Operation in MongoDB

Read operation is used to fetch or display data from a MongoDB collection.

Show All Documents

db.students.find()

Find One Document

db.students.findOne()

Find Data Using Condition

db.students.find({
   course: "BCA"
})

Update Operation in MongoDB

Update operation is used to modify existing documents in a collection.

Update One Document

db.students.updateOne(
   { name: "Harsh" },
   {
      $set: {
         marks: 95
      }
   }
)

Update Multiple Documents

db.students.updateMany(
   { course: "BCA" },
   {
      $set: {
         status: "Pass"
      }
   }
)

Delete Operation in MongoDB

Delete operation is used to remove documents from a collection.

Delete One Document

db.students.deleteOne({
   name: "Rahul"
})

Delete Multiple Documents

db.students.deleteMany({
   course: "BCA"
})

MongoDB Update Operations and Important Update Operators

In MongoDB, update operations are used when we want to change existing data inside a collection. The two most common update methods are updateOne() and updateMany().

Sample Data for Update Queries

db.students.insertMany([
   {
      name: "Harsh",
      age: 21,
      course: "BCA",
      marks: 85,
      skills: ["HTML", "CSS"]
   },
   {
      name: "Rahul",
      age: 20,
      course: "BCA",
      marks: 70,
      skills: ["JavaScript"]
   },
   {
      name: "Aman",
      age: 22,
      course: "MCA",
      marks: 90,
      skills: ["MongoDB", "Node.js"]
   }
])

1. $set Operator

The $set operator is used to update an existing field value or add a new field if it does not exist.

db.students.updateOne(
   { name: "Harsh" },
   {
      $set: {
         marks: 95,
         city: "Delhi"
      }
   }
)

2. $unset Operator

The $unset operator is used to remove a field from a document.

db.students.updateOne(
   { name: "Harsh" },
   {
      $unset: {
         city: ""
      }
   }
)

3. $inc Operator

The $inc operator is used to increase or decrease a numeric field value.

db.students.updateOne(
   { name: "Rahul" },
   {
      $inc: {
         marks: 5
      }
   }
)

db.students.updateOne(
   { name: "Rahul" },
   {
      $inc: {
         marks: -10
      }
   }
)

4. $push Operator

The $push operator is used to add a new value inside an array field.

db.students.updateOne(
   { name: "Harsh" },
   {
      $push: {
         skills: "JavaScript"
      }
   }
)

5. $each Operator with $push

The $each operator is used with $push to add multiple values inside an array at the same time.

db.students.updateOne(
   { name: "Harsh" },
   {
      $push: {
         skills: {
            $each: ["PHP", "MySQL", "React"]
         }
      }
   }
)

6. $pop Operator

The $pop operator is used to remove first or last value from an array.

db.students.updateOne(
   { name: "Harsh" },
   {
      $pop: {
         skills: 1
      }
   }
)

db.students.updateOne(
   { name: "Harsh" },
   {
      $pop: {
         skills: -1
      }
   }
)

7. $pull Operator

The $pull operator is used to remove a specific value from an array.

db.students.updateOne(
   { name: "Harsh" },
   {
      $pull: {
         skills: "CSS"
      }
   }
)

8. $addToSet Operator

The $addToSet operator adds a value to an array only if that value is not already present. It helps to avoid duplicate values.

db.students.updateOne(
   { name: "Harsh" },
   {
      $addToSet: {
         skills: "MongoDB"
      }
   }
)

9. $rename Operator

The $rename operator is used to rename a field name.

db.students.updateMany(
   {},
   {
      $rename: {
         marks: "score"
      }
   }
)

10. Update Many Documents

We can use updateMany() to update all matching documents.

db.students.updateMany(
   { course: "BCA" },
   {
      $set: {
         status: "Pass"
      }
   }
)

Quick Revision Table of MongoDB Update Operators

MongoDB CRUD Practice Questions

1. Insert one student document.
2. Insert multiple employee documents.
3. Find all records from a collection.
4. Find students whose marks are greater than 80.
5. Use $set to update marks of one student.
6. Use $unset to remove city field from one document.
7. Use $inc to increase marks by 10.
8. Use $inc to decrease age by 1.
9. Use $push to add one skill in skills array.
10. Use $each with $push to add multiple skills.
11. Use $pop to remove last skill from skills array.
12. Use $pull to remove a specific skill from skills array.
13. Use $addToSet to add a skill without duplicate entry.
14. Use updateMany() to add status field to all BCA students.
15. Delete all records with marks below 40.

MongoDB CRUD MCQ Questions

Final Conclusion

MongoDB CRUD operations are the foundation of MongoDB. Every beginner should understand how to create, read, update, and delete data properly. These operations are used in almost every website, mobile app, and backend system.