Why managed databases matter in MongoDB - See It in Action

Why Managed Databases Matter

📖 Scenario: You are working for a small online store that wants to keep track of its products and orders. Instead of managing the database yourself, you decide to use a managed database service to make your work easier and safer.

🎯 Goal: Build a simple MongoDB database with collections for products and orders. Learn how to set up data, configure a query filter, retrieve specific data, and finalize the database structure.

📋 What You'll Learn

Create a products collection with exact product documents

Create an orders collection with exact order documents

Add a filter variable to select orders with quantity greater than 2

Write a query to find orders matching the filter

Add a final index on the orders collection for faster queries

💡 Why This Matters

🌍 Real World

Managed databases help small businesses easily store and retrieve data without worrying about server setup or maintenance.

💼 Career

Understanding how to create collections, query data, and optimize with indexes is essential for database administrators and backend developers.

1

Create the products and orders collections

Create a products collection with these exact documents: { _id: 1, name: "Pen", price: 1.5 }, { _id: 2, name: "Notebook", price: 3.0 }, and a collection called orders with these exact documents: { _id: 101, product_id: 1, quantity: 5 }, { _id: 102, product_id: 2, quantity: 1 }.

MongoDB

// Create the products collection with the specified documents
// Create the orders collection with the specified documents

Need a hint?

Use insertMany to add multiple documents to each collection.

2

Add a filter to select orders with quantity greater than 2

Create a variable called filter that holds the query { quantity: { $gt: 2 } } to find orders where quantity is greater than 2.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 1.5 },
  { _id: 2, name: "Notebook", price: 3.0 }
])
db.orders.insertMany([
  { _id: 101, product_id: 1, quantity: 5 },
  { _id: 102, product_id: 2, quantity: 1 }
])

// Create the filter variable to find orders with quantity > 2
// Your code here

Need a hint?

Use $gt operator to specify 'greater than' in MongoDB queries.

3

Query the orders collection using the filter

Write a query using db.orders.find(filter) to get all orders where quantity is greater than 2.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 1.5 },
  { _id: 2, name: "Notebook", price: 3.0 }
])
db.orders.insertMany([
  { _id: 101, product_id: 1, quantity: 5 },
  { _id: 102, product_id: 2, quantity: 1 }
])

const filter = { quantity: { $gt: 2 } }

// Query the orders collection using the filter
// Your code here

Need a hint?

Use find method with the filter variable to get matching documents.

4

Add an index on the quantity field in orders

Create an index on the quantity field in the orders collection using db.orders.createIndex({ quantity: 1 }) to speed up queries.

MongoDB

db.products.insertMany([
  { _id: 1, name: "Pen", price: 1.5 },
  { _id: 2, name: "Notebook", price: 3.0 }
])
db.orders.insertMany([
  { _id: 101, product_id: 1, quantity: 5 },
  { _id: 102, product_id: 2, quantity: 1 }
])

const filter = { quantity: { $gt: 2 } }

db.orders.find(filter)

// Create an index on the quantity field in orders
// Your code here

Need a hint?

Use createIndex with the field name and 1 for ascending order.