Schema design for write-heavy workloads in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a new document into the collection.

MongoDB

db.collection.[1]({ name: "Alice", age: 30 })

Drag options to blanks, or click blank then click option'

AinsertOne

BfindOne

CupdateOne

DdeleteOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using findOne instead of insertOne will only retrieve data.

updateOne requires an existing document to update.

deleteOne removes documents, not adds.

The insertOne method adds a new document to the collection, which is essential for write-heavy workloads.

2fill in blank

medium

Complete the code to create an index that improves write performance by avoiding duplicates.

MongoDB

db.collection.createIndex({ email: 1 }, { [1]: true })

Drag options to blanks, or click blank then click option'

Asparse

Bbackground

Cunique

DexpireAfterSeconds

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sparse' does not enforce uniqueness.

Background indexing affects build time, not uniqueness.

expireAfterSeconds is for TTL indexes, unrelated here.

The unique option ensures no duplicate emails, which helps maintain data integrity in write-heavy workloads.

3fill in blank

hard

Fix the error in the update operation to increment the 'count' field by 1.

MongoDB

db.collection.updateOne({ _id: 1 }, { [1]: { count: 1 } })

Drag options to blanks, or click blank then click option'

A$inc

B$addToSet

C$push

D$set

Attempts:

3 left

💡 Hint

Common Mistakes

Using $set replaces the value instead of incrementing.

$push and $addToSet are for arrays, not numbers.

The $inc operator increments a numeric field by the specified value, perfect for counters in write-heavy workloads.

4fill in blank

hard

Fill both blanks to create a schema design that embeds comments inside posts for faster writes.

MongoDB

const commentSchema = new Schema({ text: String, date: [2] }); const postSchema = new Schema({ title: String, comments: [[1]] });

Drag options to blanks, or click blank then click option'

AcommentSchema

BDate

CString

DNumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using String instead of commentSchema for comments loses structure.

Using Number for date is not appropriate.

Embedding commentSchema inside posts allows fast writes by storing related data together. The Date type is used for the comment date.

5fill in blank

hard

Fill all three blanks to write a bulk insert operation for multiple user documents.

MongoDB

db.users.[1]([{ name: "John" }, { name: "Jane" }], { [2]: true, [3]: 1000 })

Drag options to blanks, or click blank then click option'

AinsertMany

Bordered

Cw

Dupsert

Attempts:

3 left

💡 Hint

Common Mistakes

Using insertOne inserts only one document.

Upsert is for update operations, not inserts.

insertMany inserts multiple documents at once. The ordered option controls if operations stop on error. w sets acknowledgment level for writes, important in write-heavy workloads.