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Insert One Document

MongoDB is a document-based NoSQL database that stores data in flexible, JSON-like structures called documents. When working with MongoDB, one of the most common operations is inserting a single document into a collection using the insertOne() method.

insertOne()​

The db.collection.insertOne() method allows you to insert a single document into a MongoDB collection. If the collection doesn’t already exist, MongoDB will create it automatically when the document is inserted.

// Insert single document
db.collection_name.insertOne({
key1: value1,
key2: value2,
...
})
  • db: refers to the current database you're using
  • collection: the target collection
  • The {} block is the document you want to insert

✅ Example: Insert One Student Record

Suppose you have a database called school and you want to store student details in a collection named students. Here's how you insert one student:

Syntax for inserting documents into collection​

use school  // switch to the 'school' database

// create collection
db.createCollection("students")

db.students.insertOne({
name: "John",
age: 17,
class: "12A",
subjects: ["Math", "Science"]
})
  • This creates a new document in the students collection.
  • If students does not exist, MongoDB will create it automatically.
  • The subjects field stores an array of strings.

🔐 Auto-generated _id Field When a document is inserted, MongoDB automatically adds a unique _id field to identify it:

{
"_id": ObjectId("66bfabcd1234567890efabcd"),
"name": "Sudhir",
"age": 17,
"class": "12A",
"subjects": ["Math", "Science"]
}

You can also manually set your own _id if needed.

Key Benefits​

  • No need to predefine schema
  • Collections are auto-created
  • Flexible and fast for rapid development

Conclusion​

The db.collection_name.insertOne() method is a simple yet powerful way to add individual records to a MongoDB collection. It’s ideal when you're adding single users, products, orders, or any other unit of data. Mastering this method is the first step in working effectively with MongoDB.