Why schema design matters in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a document into the 'users' collection.

MongoDB

db.users.insertOne({ name: "Alice", age: [1] })

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

A"25"

B25

Cage

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Putting numbers inside quotes makes them strings.

Using undefined variables instead of values.

The age should be a number, so 25 without quotes is correct.

2fill in blank

medium

Complete the code to find all documents where the age is greater than 30.

MongoDB

db.users.find({ age: { [1]: 30 } })

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

A$gt

B$eq

C$lt

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt which means 'less than'.

Using $eq which means 'equal to'.

The operator $gt means 'greater than'.

3fill in blank

hard

Fix the error in the update command to set the user's city to 'Paris'.

MongoDB

db.users.updateOne({ name: "Bob" }, { [1]: { city: "Paris" } })

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

Aupdate

Bset

C$update

D$set

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving out the dollar sign.

Using incorrect operator names.

The correct MongoDB operator to update fields is $set.

4fill in blank

hard

Fill both blanks to create a schema design that embeds an address inside a user document.

MongoDB

db.users.insertOne({ name: "Eve", address: { [1]: "123 Main St", [2]: "NY" } })

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

Astreet

Bcity

Cage

Dcountry

Attempts:

3 left

💡 Hint

Common Mistakes

Using unrelated fields like age or country here.

Mixing up field names.

Embedding address fields like street and city inside the user document is a common schema design.

5fill in blank

hard

Fill all three blanks to write a query that finds users older than 20 living in 'London'.

MongoDB

db.users.find({ [1]: { [2]: 20 }, address: { [3]: "London" } })

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

Aage

B$gt

Ccity

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names.

Using wrong operators.

The query filters users where age is greater than 20 and city is 'London'.