Why document design matters in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to insert a document into the collection.

MongoDB

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

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

Anull

B"25"

Cage

D25

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the number 25 in quotes, making it a string.

Using a variable name instead of a value.

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

2fill in blank

medium

Complete the code to find 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$lt

C$eq

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', so it finds ages above 30.

3fill in blank

hard

Fix the error in the update query to set the city field.

MongoDB

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

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

A$update

Bset

C$set

Dupdate

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving out the dollar sign in the operator.

Using a wrong operator like $update.

The correct operator to update fields is $set with a dollar sign.

4fill in blank

hard

Fill both blanks to create a document with an embedded address object.

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

Cstate

Dzipcode

Attempts:

3 left

💡 Hint

Common Mistakes

Using city instead of state for the second blank.

Using zipcode which is not in the example.

The address has a street and a state field, so use 'street' and 'state'.

5fill in blank

hard

Fill all three blanks to query documents with age greater than 20 and city equals 'Boston'.

MongoDB

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

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

A$gt

Bcity

C"Boston"

D$lt

Attempts:

3 left

💡 Hint

Common Mistakes

Using $lt instead of $gt for age.

Not putting Boston in quotes.

Using wrong field name instead of city.

Use $gt for age greater than 20, and match city to "Boston".