Querying nested fields at any depth in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find documents where the nested field 'address.city' equals 'Paris'.

MongoDB

db.users.find({"address[1]city": "Paris"})

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

A.

B$

C#

D_

Attempts:

3 left

💡 Hint

Common Mistakes

Using '$' instead of '.' to access nested fields.

Trying to access nested fields without quotes.

Using underscore '_' instead of dot '.' in field names.

In MongoDB, nested fields are accessed using dot notation. So to query the city inside address, use 'address.city'.

2fill in blank

medium

Complete the code to find documents where the nested field 'profile.details.age' is greater than 30.

MongoDB

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

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

A$ne

B$lt

C$eq

D$gt

Attempts:

3 left

💡 Hint

Common Mistakes

Using '$lt' which means 'less than' instead of 'greater than'.

Using '$eq' which means 'equals' instead of a comparison operator.

Forgetting the dollar sign in the operator.

The operator '$gt' means 'greater than' in MongoDB queries. It filters documents where the field value is greater than the specified number.

3fill in blank

hard

Fix the error in the query to find documents where 'settings.notifications.email' is true.

MongoDB

db.users.find({"settings[1]notifications[1]email": true})

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

A.

B,

C:

D$

Attempts:

3 left

💡 Hint

Common Mistakes

Using commas or colons instead of dots.

Using dollar signs incorrectly in field names.

Not quoting the full nested field path.

To access nested fields at any depth, MongoDB requires dot notation between each level. So use '.' between 'settings', 'notifications', and 'email'.

4fill in blank

hard

Fill both blanks to query documents where 'profile.contacts.phone.mobile' exists and is not null.

MongoDB

db.users.find({"profile[1]contacts[2]phone.mobile": { $exists: true, $ne: null } })

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

A.

B$

C_

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing different separators between nested fields.

Using underscores or dashes instead of dots.

Leaving out separators between nested fields.

Use dot notation '.' between each nested field to correctly access 'profile.contacts.phone.mobile'.

5fill in blank

hard

Fill all three blanks to query documents where 'settings.preferences.theme.color' equals 'dark'.

MongoDB

db.users.find({"settings[1]preferences[2]theme[3]color": "dark"})

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

A.

B$

C_

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using different separators like '$' or '_' instead of '.'

Mixing separators inconsistently.

Not using any separator between nested fields.

Dot notation '.' is used to access nested fields at any depth in MongoDB queries.