updateMany method in MongoDB

Introduction

The updateMany method changes multiple documents in a collection at once. It helps you fix or add data quickly without changing one by one.

You want to mark all orders as shipped for a specific customer.

You need to increase the price of all products in a category.

You want to add a new field to many user profiles at the same time.

You need to fix a typo in many documents' fields.

You want to reset a status for all tasks that are overdue.

Syntax

MongoDB

db.collection.updateMany(filter, update, options)

filter: Selects which documents to update.

update: Describes the changes to apply, usually with $set or other operators.

Examples

Sets the status to 'minor' for all users younger than 18.

MongoDB

db.users.updateMany({ age: { $lt: 18 } }, { $set: { status: "minor" } })

Adds 10 to the stock of all products in the 'books' category.

MongoDB

db.products.updateMany({ category: "books" }, { $inc: { stock: 10 } })

Marks all orders as not shipped.

MongoDB

db.orders.updateMany({}, { $set: { shipped: false } })

Sample Program

This example adds 500 to the salary of all employees in the sales department. It first inserts three employees, then updates the sales team salaries.

MongoDB

db.employees.insertMany([
  { name: "Alice", department: "sales", salary: 5000 },
  { name: "Bob", department: "sales", salary: 4500 },
  { name: "Charlie", department: "hr", salary: 4000 }
])

const result = db.employees.updateMany(
  { department: "sales" },
  { $inc: { salary: 500 } }
)

result.modifiedCount

Important Notes

updateMany changes all documents matching the filter, unlike updateOne which changes only one.

If no documents match the filter, updateMany does nothing but still returns a result.

Use update operators like $set, $inc, $unset inside the update argument to specify changes.

Summary

updateMany updates multiple documents at once based on a filter.

You must use update operators like $set or $inc to change fields.

It returns how many documents were changed.