Write concern basics in MongoDB - Mini Project: Build & Apply

Write Concern Basics in MongoDB

📖 Scenario: You are managing a small online store database using MongoDB. You want to ensure that when you add new products, the database confirms the write operation properly to avoid data loss.

🎯 Goal: Learn how to set up and use writeConcern in MongoDB to control the acknowledgment of write operations.

📋 What You'll Learn

Create a MongoDB collection named products with sample product documents.

Define a writeConcern configuration variable with w: 1.

Insert a new product document using the defined writeConcern.

Complete the insert operation with the writeConcern option applied.

💡 Why This Matters

🌍 Real World

Write concern is important in real-world applications to ensure data is safely written to the database and to avoid data loss in case of failures.

💼 Career

Understanding write concern is essential for database administrators and backend developers to maintain data integrity and reliability in production systems.

1

Create the products collection with sample data

Create a variable called products that holds an array with these exact product documents: { name: "Pen", price: 1.5 }, { name: "Notebook", price: 3 }, and { name: "Eraser", price: 0.5 }.

MongoDB

// Create the products array with the specified documents
// Your code here

Need a hint?

Use a JavaScript array with objects for each product.

2

Define the writeConcern configuration

Create a variable called writeConcern and set it to an object with w: 1 to require acknowledgment from the primary server.

MongoDB

const products = [
  { name: "Pen", price: 1.5 },
  { name: "Notebook", price: 3 },
  { name: "Eraser", price: 0.5 }
];

// Define writeConcern with w: 1
// Your code here

Need a hint?

Use an object with the key w set to 1.

3

Insert a new product using the writeConcern

Write a line to insert a new product document { name: "Marker", price: 2 } into the products collection using the writeConcern variable for the write concern option.

MongoDB

const products = [
  { name: "Pen", price: 1.5 },
  { name: "Notebook", price: 3 },
  { name: "Eraser", price: 0.5 }
];

const writeConcern = { w: 1 };

// Insert the new product with writeConcern
// Your code here

Need a hint?

Use db.products.insertOne() with the second argument as { writeConcern }.

4

Complete the insert operation with the writeConcern

Add a line to assign the result of the insert operation to a variable called insertResult using the writeConcern option, completing the database write with acknowledgment.

MongoDB

const products = [
  { name: "Pen", price: 1.5 },
  { name: "Notebook", price: 3 },
  { name: "Eraser", price: 0.5 }
];

const writeConcern = { w: 1 };

const insertResult = db.products.insertOne({ name: "Marker", price: 2 }, { writeConcern });

// Finalize the write concern setup
// Your code here

Need a hint?

Ensure the insert operation uses the writeConcern option and assigns the result to insertResult.