updateOne method in MongoDB

Introduction

The updateOne method changes a single document in a collection. It helps keep data correct and up to date.

When you want to fix a typo in one user's name in a list.

When you need to change the status of one order from 'pending' to 'shipped'.

When you want to add a new phone number to one contact's details.

When you want to mark one task as completed in a to-do list.

When you want to update the price of one product in your store.

Syntax

MongoDB

db.collection.updateOne(
  <filter>,
  <update>,
  { upsert: <boolean> }
)

The finds the document to update.

The describes the changes to make, usually with $set to change fields.

Examples

Updates the age to 30 for the first user named Alice.

MongoDB

db.users.updateOne(
  { name: "Alice" },
  { $set: { age: 30 } }
)

Changes the status of order 123 to shipped without adding a new order if not found.

MongoDB

db.orders.updateOne(
  { orderId: 123 },
  { $set: { status: "shipped" } },
  { upsert: false }
)

Updates Bob's phone number or adds a new contact if none exists.

MongoDB

db.contacts.updateOne(
  { email: "[e-mail]" },
  { $set: { phone: "555-1234" } },
  { upsert: true }
)

Sample Program

First, we add a product named Pen. Then we update its price to 2.0. Finally, we check the product details.

MongoDB

db.products.insertOne({ name: "Pen", price: 1.5, stock: 100 })
db.products.updateOne(
  { name: "Pen" },
  { $set: { price: 2.0 } }
)
db.products.find({ name: "Pen" }).toArray()

Important Notes

updateOne changes only the first document that matches the filter.

If no document matches and upsert is true, a new document is created.

Use $set to change specific fields without replacing the whole document.

Summary

updateOne updates a single document matching a filter.

Use $set inside update to change fields safely.

upsert option adds a new document if none matches.