10+ Letterdrop Interview Questions and Answers

Aggregate functions perform calculations on a set of values and return a single value.

• Common aggregate functions include COUNT, SUM, AVG, MIN, and MAX.

• COUNT returns the number of rows in a table or the number of non-null values in a column.

• SUM returns the sum of all values in a column.

• AVG returns the average of all values in a column.

• MIN returns the smallest value in a column.

• MAX returns the largest value in a column.

CTE benefits and difference between temp table and table variables

• CTE (Common Table Expression) allows for recursive queries and simplifies complex queries

• Temp tables are physical tables stored in tempdb and can be indexed and have constraints

• Table variables are stored in memory and have limited scope and no statistics

• Temp tables are better for large data sets and complex queries, while table variables are better for small data sets and simple queries

Authentication is verifying the identity of a user, while authorization is granting access to specific resources.

• Authentication confirms the identity of a user through credentials such as username and password.

• Authorization determines what resources a user can access based on their role or permissions.

• Examples of authentication include logging into a website or entering a PIN at an ATM.

• Examples of authorization include granting a user access to a specific file or allowing the...read more

Functions return a single value while stored procedures execute multiple SQL statements.

• Functions can be used in SELECT, WHERE, and HAVING clauses.

• Stored procedures can have input and output parameters.

• Functions cannot modify the database while stored procedures can.

• Functions are deterministic while stored procedures are not necessarily so.

• Examples of functions: AVG, COUNT, MAX, MIN, SUM.

• Examples of stored procedures: sp_help, sp_who, sp_adduser.

Filters in MVC are used to intercept and modify HTTP requests and responses.

• Filters are used to implement cross-cutting concerns like logging, caching, authentication, etc.

• There are five types of filters in MVC: Authorization filters, Action filters, Result filters, Exception filters, and Resource filters.

• Authorization filters are used to authenticate and authorize users before executing an action.

• Action filters are used to perform some logic before and after executing an act...read more

MVC is a software architecture pattern that separates an application into three interconnected components: Model, View, and Controller.

• Model represents the data and business logic of the application

• View is responsible for rendering the user interface

• Controller handles user input and updates the model and view accordingly

• MVC promotes separation of concerns and modularity

• Examples of MVC frameworks include Ruby on Rails, ASP.NET MVC, and Spring MVC

Bootstrap is a popular front-end framework that provides a range of benefits for web development.

• Bootstrap offers a responsive grid system that makes it easy to create mobile-friendly websites.

• It includes pre-built CSS styles and JavaScript plugins that can save time and effort in development.

• Bootstrap is well-documented and has a large community, making it easy to find support and resources.

• It is constantly updated to keep up with modern web design trends and best practices....read more

Indexes are data structures that improve the speed of data retrieval operations in a database.

• Indexes are created on one or more columns of a table.

• Types of indexes include clustered, non-clustered, unique, and full-text indexes.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes create a separate structure to store the index data.

• Unique indexes ensure that each value in the indexed column is unique, while full-text indexes enable te...read more

Web API is for building HTTP services while WCF is for building services that support multiple transport protocols.

• Web API is lightweight and ideal for building RESTful services over HTTP.

• WCF is a more heavy-duty framework that supports multiple transport protocols like HTTP, TCP, Named Pipes, etc.

• Web API is more suited for building services that are consumed by web applications while WCF is more suited for building services that are consumed by non-web applications.

• Web API i...read more

Session management in ASP.NET

• ASP.NET provides in-built session management through HttpSessionState class

• Session can be used to store user-specific data across multiple requests

• Session can be configured to use different storage options like InProc, StateServer, SQLServer

• Session can be accessed using HttpContext.Current.Session property

• Session can be secured using SSL, cookieless sessions, and timeout settings