Why querying nested data matters in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find documents where the nested field 'address.city' is 'New York'.

MongoDB

db.users.find({"address.[1]": "New York"})

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

Azip

Bstate

Ccity

Dstreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'state' or 'zip' instead of 'city' will not find the correct documents.

Forgetting to use dot notation for nested fields.

The nested field 'address.city' is accessed using dot notation as 'address.city'. So the blank should be filled with 'city'.

2fill in blank

medium

Complete the code to find documents where the nested array 'orders.items' contains 'apple'.

MongoDB

db.orders.find({"orders.[1]": "apple"})

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

Aitems

Bproduct

Cquantity

Dprice

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'product' instead of 'items' will not match the array field.

Not using dot notation for nested arrays.

To query an array field inside 'orders', we use 'orders.items'. So the blank should be 'items'.

3fill in blank

hard

Fix the error in the query to find documents where 'profile.age' is greater than 30.

MongoDB

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

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

A$lt

B$gt

C$eq

D$ne

Attempts:

3 left

💡 Hint

Common Mistakes

Using '$lt' will find ages less than 30, which is incorrect here.

Using '$eq' will find ages exactly 30, not greater.

The operator '$gt' means 'greater than'. To find ages greater than 30, use '$gt'.

4fill in blank

hard

Fill both blanks to find documents where 'comments.rating' is at least 4 and 'comments.approved' is true.

MongoDB

db.posts.find({"comments.rating": { [1]: 4 }, "comments.approved": [2] })

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

A$gte

Bfalse

Ctrue

D$lte

Attempts:

3 left

💡 Hint

Common Mistakes

Using '$lte' will find ratings less than or equal to 4, which is wrong here.

Setting approved to false will not find approved comments.

'$gte' means 'greater than or equal to', so it fits for rating at least 4. The approved field should be true, so use 'true'.

5fill in blank

hard

Fill all three blanks to create a projection that includes 'name', excludes '_id', and includes nested field 'profile.email'.

MongoDB

db.users.find({}, { [1]: 1, [2]: 0, [3]: 1 })

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

Aname

B_id

Cprofile.email

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Setting '_id' to 1 will include it, not exclude.

Forgetting to include 'profile.email' will omit the nested email field.

To include 'name' and 'profile.email', set them to 1. To exclude '_id', set it to 0.