Cognizant Senior Software Developer Interview Questions and Answers

Entity Framework is an ORM (Object-Relational Mapping) framework for .NET applications.

• ORM framework for .NET applications

• Maps database tables to classes in code

• Provides a way to query and manipulate data using LINQ

• Supports various database providers such as SQL Server, MySQL, etc.

SOLID principles are a set of five design principles for writing maintainable and scalable object-oriented code.

• Single Responsibility Principle (SRP) - a class should have only one reason to change

• Open/Closed Principle (OCP) - classes should be open for extension but closed for modification

• Liskov Substitution Principle (LSP) - objects of a superclass should be replaceable with objects of its subclasses without affecting the program's correctness

• Interface Segregation Principle...read more

Design patterns are reusable solutions to common problems in software design.

• Design patterns provide a template for solving recurring design problems in software development.

• They help in making code more maintainable, scalable, and efficient.

• Examples include Singleton, Factory, Observer, and Strategy patterns.

CTE stands for Common Table Expression in SQL, used to create temporary result sets that can be referenced within a query.

• CTEs are defined using the WITH keyword

• They can be recursive or non-recursive

• CTEs improve readability and maintainability of complex queries

• Example: WITH cte AS (SELECT * FROM table_name) SELECT * FROM cte

Singleton is a design pattern that restricts the instantiation of a class to one object. Immutable objects cannot be changed after creation.

• Singleton pattern is used to ensure only one instance of a class is created and provide a global point of access to it.

• Mutable objects can be changed after creation, while immutable objects cannot.

• Immutable objects are thread-safe and can be shared across multiple threads without the need for synchronization.

• Examples of immutable objects ...read more