TCS Backend Associate Interview Questions and Answers

I chose Flask over Django and FastAPI due to its simplicity, flexibility, and ease of use for smaller projects.

• Flask is lightweight and minimalistic, making it easier to set up and use for smaller projects.

• Flask allows for more flexibility in terms of project structure and customization compared to Django.

• Flask is well-suited for rapid prototyping and smaller applications where simplicity is key.

• Django, on the other ha...read more

Flask request and response block code snippet

• Use Flask's request object to access incoming request data

• Use Flask's jsonify function to create a JSON response

• Handle different HTTP methods like GET, POST, etc. in the route function

ORM stands for Object-Relational Mapping, a programming technique for converting data between incompatible type systems in object-oriented programming languages.

• ORM is used to map objects from an application to tables in a relational database.

• It simplifies data manipulation by allowing developers to work with objects instead of SQL queries.

• Popular ORM tools include Hibernate for Java, Entity Framework for .NET, and Seq

Use ORM code to select item from a table in database.

• Use ORM query methods like find(), findOne(), or where() to select items from a table.

• Specify the table name and any conditions for the selection.

• Example: User.find({ where: { id: 1 } }) will select a user with id 1 from the User table.

Node.js is a runtime environment that allows you to run JavaScript code outside of a web browser.

• Node.js is built on Chrome's V8 JavaScript engine.

• It uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

• Node.js is commonly used for building server-side applications and APIs.

• It has a large ecosystem of open-source libraries and frameworks, such as Express.js.

Middleware is a software component that acts as a bridge between an application's request and response.

• Middleware functions have access to the request and response objects

• They can modify the request and response objects

• Middleware can be used for tasks like authentication, logging, error handling, etc.

A promise is an object representing the eventual completion or failure of an asynchronous operation.

• Promises are used to handle asynchronous operations in JavaScript.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() to handle success and .catch() to handle errors.

• Example: new Promise((resolve, reject) => { setTimeout(() => resolve('Done!'), 1000); });

promise.all is a method in JavaScript that takes an array of promises and returns a single promise that resolves when all of the input promises have resolved.

• Used to handle multiple asynchronous operations at once

• Returns a single promise that resolves when all input promises have resolved

• If any of the input promises is rejected, the returned promise is rejected with the reason of the first rejected promise

A callback is a function passed as an argument to another function to be executed later.

• Callbacks are commonly used in asynchronous programming to handle tasks that take time to complete.

• They are often used in event handling, timers, and AJAX requests.

• Callbacks can be synchronous or asynchronous, depending on when they are executed.

• Example: setTimeout(callback, 1000) will execute the callback function after 1 second.

I am a passionate Backend Developer with 5 years of experience in building scalable and efficient web applications.

• 5 years of experience in backend development

• Proficient in programming languages like Java, Python, and Node.js

• Strong understanding of database management systems such as MySQL and MongoDB

• Experience in developing RESTful APIs and microservices

• Familiar with cloud technologies like AWS and Azure

Find pairs from list whose sum is equal to target

• Iterate through the list and for each element, check if the target minus the element exists in a hashmap

• If it exists, add the pair to the result list

• If it doesn't exist, add the current element to the hashmap