$min and $max update operators in MongoDB - Mini Project: Build & Apply

Using $min and $max Update Operators in MongoDB

📖 Scenario: You are managing a MongoDB collection that stores information about products in a store. Each product has a price field. You want to update the prices so that they never go below a certain minimum price or above a certain maximum price.

🎯 Goal: Learn how to use the $min and $max update operators in MongoDB to adjust product prices to stay within specified limits.

📋 What You'll Learn

Create a MongoDB collection named products with specific product documents.

Define minimum and maximum price limits as variables.

Use the $min operator to update product prices only if the new price is lower than the current price.

Use the $max operator to update product prices only if the new price is higher than the current price.

💡 Why This Matters

🌍 Real World

Retail stores often need to adjust product prices to stay competitive or maintain profit margins. Using $min and $max operators helps automate price adjustments safely.

💼 Career

Database administrators and backend developers use MongoDB update operators like $min and $max to maintain data integrity and enforce business rules on data.

1

Create the products collection with initial data

Create a MongoDB collection called products and insert these exact documents: { _id: 1, name: "Pen", price: 10 }, { _id: 2, name: "Notebook", price: 20 }, and { _id: 3, name: "Eraser", price: 5 }.

MongoDB

// Insert the specified documents into the products collection
// Your code here

Need a hint?

Use db.products.insertMany() to add multiple documents at once.

2

Define minimum and maximum price limits

Create two variables called minPrice and maxPrice and set them to 8 and 18 respectively.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 10 },
  { _id: 2, name: "Notebook", price: 20 },
  { _id: 3, name: "Eraser", price: 5 }
])

// Define minPrice and maxPrice variables
// Your code here

Need a hint?

Use const to create variables for the price limits.

3

Use $min to lower prices only if new price is less

Write an update command using db.products.updateMany() that uses the $min operator to set the price to minPrice only if minPrice is less than the current price.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 10 },
  { _id: 2, name: "Notebook", price: 20 },
  { _id: 3, name: "Eraser", price: 5 }
])

const minPrice = 8;
const maxPrice = 18;

// Update prices using $min operator
// Your code here

Need a hint?

Use updateMany with an empty filter {} to update all documents.

4

Use $max to raise prices only if new price is more

Write an update command using db.products.updateMany() that uses the $max operator to set the price to maxPrice only if maxPrice is greater than the current price.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 10 },
  { _id: 2, name: "Notebook", price: 20 },
  { _id: 3, name: "Eraser", price: 5 }
])

const minPrice = 8;
const maxPrice = 18;

db.products.updateMany({}, { $min: { price: minPrice } })

// Update prices using $max operator
// Your code here

Need a hint?

Use updateMany again with $max to raise prices where needed.