$replaceRoot for restructuring in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to replace the root document with the "details" field.

MongoDB

db.collection.aggregate([{ $replaceRoot: { newRoot: [1] } }])

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

A$$ROOT

B$details

C$root

D$_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using $$ROOT instead of $details causes no change.

Using $root or $_id replaces with wrong fields.

The $replaceRoot stage replaces the root document with the specified field. Using $details sets the root to the "details" field.

2fill in blank

medium

Complete the code to replace the root with the "info" field inside "profile".

MongoDB

db.collection.aggregate([{ $replaceRoot: { newRoot: [1] } }])

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

A$info.profile

B$profile.info.details

C$profile_info

D$profile.info

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of fields like $info.profile is incorrect.

Using underscores instead of dots breaks the path.

To replace the root with a nested field, use the full path with dot notation. Here, $profile.info points to the "info" field inside "profile".

3fill in blank

hard

Fix the error in the code to correctly replace the root with the "address" field.

MongoDB

db.collection.aggregate([{ $replaceRoot: { newRoot: [1] } }])

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

A$address

Baddress

C$$address

Daddress$

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the dollar sign causes an error.

Using double dollar signs or trailing dollar signs is invalid.

The newRoot value must be a field path starting with a dollar sign. Using $address correctly references the "address" field.

4fill in blank

hard

Fill both blanks to replace the root with the "contact" field and rename it to "info".

MongoDB

db.collection.aggregate([{ $replaceRoot: { newRoot: { [1]: [2] } } }])

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

Ainfo

B$contact

C$info

Dcontact

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong field path for the value.

Swapping key and value positions.

To rename the root field, create a new object with the desired key "info" and assign it the value of the "contact" field using $contact.

5fill in blank

hard

Fill all three blanks to replace the root with a new object containing "name", "email", and "phone" fields from "user".

MongoDB

db.collection.aggregate([{ $replaceRoot: { newRoot: { name: [1], email: [2], phone: [3] } } }])

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

A$user.name

B$user.email

C$user.phone

D$user.contact

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong field paths or mixing keys.

Using a non-existent field like $user.contact.

Each field in the new root object should be assigned the corresponding nested field from "user" using dot notation with a dollar sign.