$rename operator for field names in MongoDB - Mini Project: Build & Apply

$rename Operator for Field Names in MongoDB

📖 Scenario: You work in a library database. The book records have a field called title but the team wants to rename it to bookTitle for clarity.

🎯 Goal: Learn how to use the MongoDB $rename operator to rename a field in all documents of a collection.

📋 What You'll Learn

Create a collection called books with three documents having fields title and author.

Create a filter variable called filter to select all documents.

Use the $rename operator in an update command to rename the title field to bookTitle.

Complete the update command to apply the rename to all matching documents.

💡 Why This Matters

🌍 Real World

Renaming fields in a database is common when improving data clarity or adapting to new requirements without losing existing data.

💼 Career

Database administrators and backend developers often need to update database schemas safely using operators like $rename.

1

Create the books collection with sample documents

Create a collection called books and insert these three documents exactly: { title: "1984", author: "George Orwell" }, { title: "Brave New World", author: "Aldous Huxley" }, and { title: "Fahrenheit 451", author: "Ray Bradbury" }.

MongoDB

// Insert the three book documents into the books collection
// Your code here

Need a hint?

Use db.books.insertMany([...]) with the exact documents inside the array.

2

Create a filter to select all documents

Create a variable called filter and set it to an empty object {} to select all documents in the collection.

MongoDB

db.books.insertMany([
  { title: "1984", author: "George Orwell" },
  { title: "Brave New World", author: "Aldous Huxley" },
  { title: "Fahrenheit 451", author: "Ray Bradbury" }
])

// Create a filter to select all documents
// Your code here

Need a hint?

Use const filter = {} to select all documents.

3

Use $rename operator to rename the field

Create an update object called update that uses the $rename operator to rename the field title to bookTitle.

MongoDB

db.books.insertMany([
  { title: "1984", author: "George Orwell" },
  { title: "Brave New World", author: "Aldous Huxley" },
  { title: "Fahrenheit 451", author: "Ray Bradbury" }
])

const filter = {}

// Create an update object using $rename to rename title to bookTitle
// Your code here

Need a hint?

Use { $rename: { title: "bookTitle" } } as the update object.

4

Apply the update to rename the field in all documents

Use db.books.updateMany with the filter and update objects to rename the title field to bookTitle in all documents.

MongoDB

db.books.insertMany([
  { title: "1984", author: "George Orwell" },
  { title: "Brave New World", author: "Aldous Huxley" },
  { title: "Fahrenheit 451", author: "Ray Bradbury" }
])

const filter = {}

const update = { $rename: { title: "bookTitle" } }

// Use updateMany with filter and update to rename the field
// Your code here

Need a hint?

Use db.books.updateMany(filter, update) to apply the rename to all documents.