Single field index in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a single field index on the 'name' field in MongoDB.

MongoDB

db.collection.createIndex({ [1]: 1 })

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

A"email"

B"name"

C"age"

D"address"

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong field name.

Forgetting to put the field name in quotes.

The code creates an ascending index on the 'name' field. This helps queries that filter or sort by 'name' run faster.

2fill in blank

medium

Complete the code to create a descending index on the 'score' field.

MongoDB

db.collection.createIndex({ score: [1] })

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

A-1

B1

C0

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of -1 for descending order.

Using 0 or 2 which are invalid index directions.

Using -1 creates a descending index on the 'score' field, which helps queries that sort by score in descending order.

3fill in blank

hard

Fix the error in the code to create an index on the 'email' field.

MongoDB

db.collection.createIndex({ [1]: 1 })

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

AemailField

Bemail

C'email'

D"email"

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the field name.

Using single quotes which may cause errors in some shells.

The field name must be a string in quotes. Using "email" is correct syntax for MongoDB index creation.

4fill in blank

hard

Fill both blanks to create an ascending index on the 'username' field with a custom name 'user_index'.

MongoDB

db.collection.createIndex({ [1]: [2] }, { name: "user_index" })

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

A"username"

B1

C-1

D"user"

Attempts:

3 left

💡 Hint

Common Mistakes

Using -1 instead of 1 for ascending order.

Not quoting the field name.

The index is created on the 'username' field in ascending order (1). The index is named 'user_index' for easy reference.

5fill in blank

hard

Fill all three blanks to create a unique descending index on the 'email' field with the name 'email_unique'.

MongoDB

db.collection.createIndex({ [1]: [2] }, { [3]: true, name: "email_unique" })

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

A"email"

B-1

Cunique

Dsparse

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to set unique to true.

Using ascending order instead of descending.

Not quoting the field name.

This creates a unique index on the 'email' field in descending order. The 'unique: true' option enforces uniqueness.