Index creation in Ruby on Rails - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add an index on the users table for the email column.

Ruby on Rails

add_index :users, :[1]

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

Aname

Bage

Cemail

Dcreated_at

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a column that is rarely searched, like created_at.

Forgetting to specify the column name.

The add_index method adds an index on the specified column. Here, we want to index the email column.

2fill in blank

medium

Complete the code to add a unique index on the username column in the users table.

Ruby on Rails

add_index :users, :username, unique: [1]

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

Atrue

Bfalse

Cnil

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using unique: false which does not enforce uniqueness.

Omitting the unique option.

Setting unique: true ensures that the index enforces uniqueness on the username column.

3fill in blank

hard

Fix the error in the code to add a multi-column index on first_name and last_name.

Ruby on Rails

add_index :users, [1]

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

A[:first_name, :last_name]

B:first_name, :last_name

Cfirst_name, last_name

D['first_name', 'last_name']

Attempts:

3 left

💡 Hint

Common Mistakes

Passing columns as separate arguments instead of an array.

Using strings instead of symbols.

Multi-column indexes require an array of symbols representing the columns.

4fill in blank

hard

Fill both blanks to add an index on the orders table for the user_id column with a custom name.

Ruby on Rails

add_index :orders, :[1], name: '[2]'

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

Auser_id

Border_user_index

Cuser_index

Dcustomer_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong column name like customer_id.

Not providing a meaningful index name.

The index is on the user_id column, and the custom index name is order_user_index.

5fill in blank

hard

Fill all three blanks to add a unique index on the email column of the customers table with a custom name.

Ruby on Rails

add_index :customers, :[1], unique: [2], name: '[3]'

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

Aemail

Btrue

Cunique_email_index

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Setting unique to false which does not enforce uniqueness.

Using a generic or missing index name.

This code adds a unique index on the email column with the name unique_email_index.