Ruby, Rails & SQL Online Test

The Ruby, Rails & SQL Online Test uses scenario-based MCQs to evaluate candidates on their proficiency in the Ruby programming language, the Rails web framework, and SQL database. The test assesses candidates' understanding of topics such as model-view-controller architecture, ActiveRecord, database migrations, SQL queries, and database design principles. Candidates are evaluated on their ability to use Ruby and Rails to interact with databases, design database schemas, and write optimized and secure SQL queries for data manipulation and retrieval.

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Screen candidates with a 45 mins test

Test duration: 45 mins

Difficulty level: Moderate

Availability: Ready to use

Questions:

5 Ruby MCQs
5 Rails MCQs
5 SQL MCQs
1 Ruby Coding Question

Covered skills:

Ruby Basics

Ruby OOPs

Rails Fundamentals

Rails MVC

REST APIs in Rails

SQL CRUD Operations

SQL Joins and Indexes

Ruby Coding

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The Ruby, Rails & SQL Online Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

Ability to write clean and efficient Ruby code
Understanding of object-oriented programming principles in Ruby
Proficiency in Rails framework and its fundamentals
Knowledge of Model-View-Controller (MVC) architecture in Rails
Experience in developing REST APIs in Rails
Familiarity with SQL CRUD operations
Understanding of SQL joins and indexes
Ability to solve coding problems using Ruby

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How we design questions

These are just a small sample from our library of 15,000+ questions. The actual questions on this Ruby, Rails & SQL Test will be non-googleable.

🧐 Question
Easy Arrays Strings Arrays Strings	Solve
Check the following Ruby code: We want the following execution result: - Commit - PR - Merge What should we replace __BLOCK__ with to achieve this?
Medium Class and Self OOPs	Solve
What is the execution result of the following Ruby code?
Easy Exceptions Exceptions OOPs	Solve
What is the result of following Ruby code:
Medium New Class OOPs Singleton	Solve
Check the following Ruby code: Which all of the following statements should replace __BLOCK__ to have "Marvel" as execution result? A: Sample.new.class.ciao B: Sample.class.new.ciao C: Sample.new.ciao D: Sample.ciao
Hard Movie query problem	Solve
Our intern created the following model scope and they want to use in this view: Which of these code snippets they use to fetch the correct results, and avoid the N+1 query issue?
Medium Multi Select JOIN GROUP BY	Solve
Consider the following SQL table: How many rows does the following SQL query return?
Medium nth highest sales Nested queries User Defined Functions	Solve
Consider the following SQL table: Which of the following SQL commands will find the ‘nth highest Sales’ if it exists (returns null otherwise)?
Medium Select & IN Nested queries	Solve
Consider the following SQL table: Which of the following SQL queries would return the year when neither a football or cricket winner was chosen?
Medium Sorting Ubers Nested queries Join Comparison operators	Solve
Consider the following SQL table: What will be the first two tuples resulting from the following SQL command?
Hard With, AVG & SUM MAX() MIN() Aggregate functions	Solve
Consider the following SQL table: How many tuples does the following query return?
Easy Registration Queue Logic Queues	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
Medium Visitors Count Strings Logic	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill
	Easy Arrays Strings Arrays Strings	2 mins Ruby	Solve
Check the following Ruby code: We want the following execution result: - Commit - PR - Merge What should we replace __BLOCK__ with to achieve this?
	Medium Class and Self OOPs	2 mins Ruby	Solve
What is the execution result of the following Ruby code?
	Easy Exceptions Exceptions OOPs	2 mins Ruby	Solve
What is the result of following Ruby code:
	Medium New Class OOPs Singleton	2 mins Ruby	Solve
Check the following Ruby code: Which all of the following statements should replace __BLOCK__ to have "Marvel" as execution result? A: Sample.new.class.ciao B: Sample.class.new.ciao C: Sample.new.ciao D: Sample.ciao
	Hard Movie query problem	4 mins Rails	Solve
Our intern created the following model scope and they want to use in this view: Which of these code snippets they use to fetch the correct results, and avoid the N+1 query issue?
	Medium Multi Select JOIN GROUP BY	2 mins SQL	Solve
Consider the following SQL table: How many rows does the following SQL query return?
	Medium nth highest sales Nested queries User Defined Functions	3 mins SQL	Solve
Consider the following SQL table: Which of the following SQL commands will find the ‘nth highest Sales’ if it exists (returns null otherwise)?
	Medium Select & IN Nested queries	3 mins SQL	Solve
Consider the following SQL table: Which of the following SQL queries would return the year when neither a football or cricket winner was chosen?
	Medium Sorting Ubers Nested queries Join Comparison operators	3 mins SQL	Solve
Consider the following SQL table: What will be the first two tuples resulting from the following SQL command?
	Hard With, AVG & SUM MAX() MIN() Aggregate functions	2 mins SQL	Solve
Consider the following SQL table: How many tuples does the following query return?
	Easy Registration Queue Logic Queues	30 mins Coding	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Medium Visitors Count Strings Logic	30 mins Coding	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill	💪 Difficulty	⌛ Time
	Arrays Strings Arrays Strings	Ruby	Easy	2 mins	Solve
Check the following Ruby code: We want the following execution result: - Commit - PR - Merge What should we replace __BLOCK__ with to achieve this?
	Class and Self OOPs	Ruby	Medium	2 mins	Solve
What is the execution result of the following Ruby code?
	Exceptions Exceptions OOPs	Ruby	Easy	2 mins	Solve
What is the result of following Ruby code:
	New Class OOPs Singleton	Ruby	Medium	2 mins	Solve
Check the following Ruby code: Which all of the following statements should replace __BLOCK__ to have "Marvel" as execution result? A: Sample.new.class.ciao B: Sample.class.new.ciao C: Sample.new.ciao D: Sample.ciao
	Movie query problem	Rails	Hard	4 mins	Solve
Our intern created the following model scope and they want to use in this view: Which of these code snippets they use to fetch the correct results, and avoid the N+1 query issue?
	Multi Select JOIN GROUP BY	SQL	Medium	2 mins	Solve
Consider the following SQL table: How many rows does the following SQL query return?
	nth highest sales Nested queries User Defined Functions	SQL	Medium	3 mins	Solve
Consider the following SQL table: Which of the following SQL commands will find the ‘nth highest Sales’ if it exists (returns null otherwise)?
	Select & IN Nested queries	SQL	Medium	3 mins	Solve
Consider the following SQL table: Which of the following SQL queries would return the year when neither a football or cricket winner was chosen?
	Sorting Ubers Nested queries Join Comparison operators	SQL	Medium	3 mins	Solve
Consider the following SQL table: What will be the first two tuples resulting from the following SQL command?
	With, AVG & SUM MAX() MIN() Aggregate functions	SQL	Hard	2 mins	Solve
Consider the following SQL table: How many tuples does the following query return?
	Registration Queue Logic Queues	Coding	Easy	30 mins	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Visitors Count Strings Logic	Coding	Medium	30 mins	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

Test candidates on core Ruby, Rails & SQL Hiring Test topics

Ruby Basics: Ruby Basics refers to the fundamental concepts and syntax of the Ruby programming language. This skill should be measured in the test to assess the candidate's understanding of variables, data types, control structures, and basic programming concepts in Ruby.

Ruby OOPs: Ruby OOPs (Object-Oriented Programming) refers to the ability of a candidate to understand and apply object-oriented principles in Ruby, such as encapsulation, inheritance, and polymorphism. This skill is important to assess as Ruby heavily relies on object-oriented programming concepts and encourages the use of classes and objects.

Rails Fundamentals: Rails Fundamentals assess the candidate's knowledge of the core concepts and features of Ruby on Rails framework. This includes understanding the Model-View-Controller (MVC) architecture, routing, database migrations, and basic CRUD operations in Rails. Evaluating this skill is crucial as Rails is a popular web application framework widely used in industry.

Rails MVC: Rails MVC (Model-View-Controller) refers to the ability to understand and implement the architectural pattern used in Ruby on Rails applications. This includes designing and manipulating models, rendering views, and handling user input through controllers. Assessing this skill helps measure the candidate's understanding of Rails' MVC structure and their ability to develop well-structured and maintainable web applications.

REST APIs in Rails: REST APIs in Rails assess the candidate's knowledge of building, consuming, and testing RESTful APIs using Ruby on Rails. This includes understanding REST principles, designing API endpoints, handling HTTP methods, and implementing authentication and authorization. Measuring this skill is important as APIs play a crucial role in modern application development and integration.

SQL CRUD Operations: SQL CRUD Operations refer to the ability to perform Create, Read, Update, and Delete operations on a database using SQL. This skill should be measured in the test to evaluate the candidate's proficiency in writing SQL queries to manipulate data and interact with databases effectively.

SQL Joins and Indexes: SQL Joins and Indexes assess the candidate's understanding of joining tables and optimizing query performance using indexes in SQL. This includes knowledge of different types of joins (inner join, outer join, etc.) and the usage of indexes to improve query execution time. Evaluating this skill is important as SQL is a widely used language for relational databases, and efficient querying is crucial for ensuring database performance.

Ruby Coding: Ruby Coding refers to the candidate's ability to write clean, efficient, and well-structured Ruby code. This includes following coding conventions, utilizing appropriate data structures and algorithms, and applying best practices in Ruby development. Assessing this skill helps measure the candidate's ability to produce high-quality code and maintainable software solutions.

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