WebMD Interview Questions and Answers

Joins in SQL are used to combine rows from two or more tables based on a related column between them.

• Joins are used to retrieve data from multiple tables based on a related column between them

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column

I deploy my application using containerization and continuous integration/continuous deployment (CI/CD) pipelines.

• Utilize Docker to containerize the application for easy deployment and scalability

• Use CI/CD pipelines such as Jenkins or GitLab CI to automate the deployment process

• Deploy to cloud platforms like AWS, Azure, or Google Cloud for reliable hosting

• Implement monitoring and logging tools like Prometheus and ...read more

Caching can be implemented using RabbitMQ by storing frequently accessed data in memory.

• Set up a RabbitMQ server to act as a message broker

• Publish data to RabbitMQ when it is fetched from the database

• Subscribe to messages in your Node.js application and store the data in memory

• Check the cache before fetching data from the database

Node.js is single-threaded, but can handle multiple threads using child processes or worker threads.

• Use child processes to run multiple instances of Node.js

• Use worker threads for CPU-intensive tasks

• Leverage the cluster module to create a pool of worker processes

Node.js uses event-driven architecture to handle asynchronous tasks while synchronous tasks are executed in a blocking manner.

• Node.js uses event loop to handle asynchronous tasks by offloading them to the system, allowing other tasks to continue without waiting.

• Synchronous tasks are executed in a blocking manner, meaning the program waits for each task to complete before moving on to the next one.

• Node.js provides ...read more

Fork creates a new process while spawn launches a new process asynchronously.

• Fork is used to create child processes in Node.js, typically for running separate instances of the same application.

• Spawn is used to launch a new process asynchronously, allowing for communication between the parent and child processes.

• Fork is commonly used in cluster mode for load balancing in Node.js applications.

• Spawn is used for execu...read more

Insertion sort is a simple sorting algorithm that builds the final sorted array one item at a time.

• It starts by comparing the first two elements and swapping them if necessary.

• Then it compares the second and third elements and swaps them if necessary, and so on.

• It continues this process until the entire array is sorted.

• It has a time complexity of O(n^2) in the worst case.

• It is efficient for small data sets or part...read more

OOP (Object-Oriented Programming) is a programming paradigm based on objects and classes to structure software design.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Mechanism to create a new class using properties and methods of an existing class (e.g., a 'Dog' class inheriting from an 'Animal' class).

• Polymorphism: Ability to present the same interfac...read more