GKM IT Interview Questions and Answers

Virtual DOM is a lightweight copy of the actual DOM, useState is a hook for managing state in functional components, and Hooks are functions that let you use state and other React features in functional components.

• Virtual DOM is a lightweight copy of the actual DOM that React uses to improve performance by updating only the necessary parts of the actual DOM.

• useState is a hook in React that allows functional components to have state. It returns an array with the current state ...read more

Triggers in SQL are special stored procedures that are automatically executed when certain events occur in a database. Indexes in SQL are used to speed up the retrieval of data from tables.

• Types of triggers: DML triggers (insert, update, delete), DDL triggers (create, alter, drop), and Logon triggers.

• Indexes in SQL are used to quickly retrieve data from tables. Types of indexes include clustered, non-clustered, unique, and composite indexes.

• Example: CREATE TRIGGER trgAfterIns...read more

var keyword has function scope, let keyword has block scope. Closure function is a function defined inside another function.

• var keyword has function scope, let keyword has block scope

• Variables declared with var are hoisted to the top of their function, let variables are not hoisted

• Closure function is a function defined inside another function, has access to the outer function's variables

MVVM is a design pattern that separates the UI from the business logic, promoting code reusability and maintainability.

• MVVM stands for Model-View-ViewModel

• Model represents the data and business logic

• View is the UI components that the user interacts with

• ViewModel acts as a mediator between the Model and View, handling user inputs and updating the Model

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

• Examples of design patterns include Singleton, Fact...read more

Middleware in .Net Core is a software component that acts as a bridge between an application's request processing pipeline and the server.

• Middleware components are executed in the order they are added to the pipeline.

• They can perform tasks like authentication, logging, error handling, etc.

• Middleware can be added using the 'UseMiddleware' method in the 'Configure' method of Startup class.

Clean Architecture is a software design approach that separates concerns and enforces a clear structure for code organization.

• Clear separation of concerns between different layers (e.g. presentation, domain, data)

• Dependency Rule: inner layers should not depend on outer layers

• Use of interfaces to define boundaries between layers

• Focus on testability and maintainability

• Examples: Hexagonal Architecture, Onion Architecture

SOLID principles are a set of five design principles in object-oriented programming to make software designs more understandable, flexible, and maintainable.

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

• Open/Closed Principle (OCP) - Software entities 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...read more