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.

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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About the Ruby, Rails & SQL Test

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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Use Adaface tests trusted by recruitment teams globally. Adaface skill assessments measure on-the-job skills of candidates, providing employers with an accurate tool for screening potential hires.

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Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

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 Syntax Exception Handling	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 Eager Loading N+1 Query Issue	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 Sql Join Data Analysis	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 Sorting By Custom Order	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 String Parsing Character Counting	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 Syntax Exception Handling	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 Eager Loading N+1 Query Issue	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 Sql Join Data Analysis	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 Sorting By Custom Order	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 String Parsing Character Counting	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 Syntax Exception Handling	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 Eager Loading N+1 Query Issue	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 Join Data Analysis	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 Sorting By Custom Order	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 String Parsing Character Counting	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.

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Why you should use Pre-employment Ruby, Rails & SQL Online Test?

The Ruby, Rails & SQL Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

Ability to write clean and efficient Ruby code
Understanding of object-oriented programming concepts in Ruby
Experience with building web applications using Ruby on Rails framework
Familiarity with the Model-View-Controller (MVC) architecture in Rails
Knowledge of designing and implementing REST APIs in Rails
Proficiency in performing CRUD operations using SQL
Understanding of SQL joins and indexes for efficient database querying
Ability to solve complex coding problems using Ruby
Experience with version control systems for code management
Proficiency in writing testable code and unit test cases

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the Ruby, Rails & SQL Online Test?

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.

Full list of covered topics

The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for Ruby, Rails & SQL Test to be based on.

Ruby syntax

Variables and data types in Ruby

Control flow in Ruby

Functions and methods in Ruby

Class and object in Ruby

Inheritance and polymorphism in Ruby

Rails directory structure

Routing in Rails

Models and database in Rails

Views and templates in Rails

Controllers and actions in Rails

Working with RESTful APIs in Rails

User authentication and authorization in Rails

Creating and manipulating database tables using SQL

Selecting and filtering data in SQL

Updating and deleting data in SQL

Joining multiple tables in SQL

Indexing and optimizing SQL queries

Implementing basic Ruby coding problems

Using Ruby libraries and gems

Debugging Ruby code

Error handling and exception catching in Ruby

Testing Ruby code using frameworks like RSpec

Understanding Ruby blocks and iterators

Working with arrays and hashes in Ruby

File I/O operations in Ruby

Understanding Ruby classes and modules

Implementing associations between Rails models

Using Git version control in Rails projects

Deploying Rails applications to production servers

Working with sessions and cookies in Rails

Implementing pagination and sorting in Rails

Query optimization in SQL

Creating database indexes in Rails

Deploying RESTful APIs in Rails

Configuring and using caching in Rails

Creating and utilizing Rails plugins

Implementing background jobs in Rails

Interacting with external APIs in Rails

Handling database migrations in Rails

Creating and using partials in Rails views

Implementing nested resources in Rails

Building search functionality in Rails

Implementing file uploads in Rails

Implementing internationalization in Rails

Securing Rails applications against common vulnerabilities

Working with JSON data in Rails

Optimizing Ruby code for performance

Creating and using helper methods in Rails views

Using environment variables in Rails applications

Implementing API versioning in Rails

Handling concurrency and thread safety in Ruby

Working with ActiveRecord associations in Rails

Implementing data validations in Rails models

Creating and consuming web services in Rails

Optimizing SQL queries using indexes

Implementing full-text search in SQL

Understanding database normalization in SQL

Implementing transaction management in Rails

Working with time and dates in Ruby

What roles can I use the Ruby, Rails & SQL Online Test for?

Ruby Developer
Rails Developer
RoR Developer

How is the Ruby, Rails & SQL Online Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

Understanding of software development best practices and coding standards
Knowledge of web security principles and common vulnerabilities
Ability to optimize and improve application performance
Experience with deploying and managing applications on cloud platforms
Knowledge of asynchronous programming and background job processing
Understanding of caching mechanisms for improving application speed
Experience with integrating third-party libraries and APIs
Familiarity with front-end technologies like HTML, CSS, and JavaScript
Ability to collaborate effectively with cross-functional teams
Strong problem-solving and analytical skills
Excellent communication and documentation skills

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on experience.

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Have questions about the Ruby, Rails & SQL Hiring Test?

What is Ruby, Rails & SQL Test?

The Ruby, Rails & SQL Test is designed to evaluate a candidate's proficiency in Ruby, Rails, and SQL. It's utilized by recruiters to identify skilled developers, ensuring they have the right technical knowledge necessary for the role.

Can I combine Ruby, Rails & SQL Test with Python questions?

Yes, recruiters can request a custom test with multiple skills in one assessment. For more details on how we assess Python skills, you can check the Python Online Test.

What kind of questions are included in the Ruby, Rails & SQL Test?

The test includes:

5 Ruby questions
5 Rails questions
5 SQL questions
1 Ruby coding question These cover basics, OOPs, MVC, REST APIs, CRUD operations, Joins, and Indexes.

How to use Ruby, Rails & SQL Test in my hiring process?

Use this test as a pre-screening tool early in your recruitment process. Add the assessment link in your job post, or directly invite candidates via email. This helps find skilled candidates faster.

Can I test Ruby on Rails together with SQL?

Yes, combining Ruby on Rails with SQL is recommended for full-stack roles. Check out the Ruby & Rails Test for assessing both skills.

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

Non-googleable questions
IP proctoring
Screen proctoring
Web proctoring
Webcam proctoring
Plagiarism detection
Secure browser
Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

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I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

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Along with scorecards that report the performance of the candidate in detail, you also receive a comparative analysis against the company average and industry standards.

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