What is Object Relational Mapper (ORM)

An ORM is an application or system that aids in the conversion of data within a relational database management system (RDBMS) and the object model that is necessary for use within object-oriented programming. The O/RM hydrates the object with the data from the database, or creates the SQL statements that will save the object data into the database.
Examples of ORM products are Hibernate, NHibernate, Entity Framework, and Linq-to-SQL etc.

Source: Exam Ref 70-486- Developing ASP.NET MVC 4 Web Applications

What is Entity Framework

Entity Framework (EF) is an object-relational mapper that enables .NET developers to work with relational data using domain-specific objects. It eliminates the need for most of the data-access code that developers usually need to write.

Entity Framework is Microsoft’s recommended data access technology for new applications.

Source: msdn.microsoft.com

What is Loose Coupling in Software Engineering

Loose coupling is an architectural approach in which the designer seeks to limit the amount of interdependencies between various parts of a system. By reducing interdependencies, changes to one area of an application are less likely to affect another area. Also, by eliminating interdependencies, you ensure that your application is more maintainable, testable, and flexible, which tends to result in a more stable system.

Source: Exam Ref 70-486- Developing ASP.NET MVC 4 Web Applications

What is Separation of Concern (SoC)

Separation of concern (SoC) is a software development concept that separates a computer program into different sections, or concerns, in which each concern has a different purpose. By separating these sections, each can
encapsulate information that can be developed and updated independently.

Source: Exam Ref 70-486- Developing ASP.NET MVC 4 Web Applications

What is an Application

An application is simply a set of functionality: a screen or set of screens that displays information, a way to persist data across uses, and a way to make business decisions.

Source: Exam Ref 70-486- Developing ASP.NET MVC 4 Web Applications

What are WebSockets

WebSockets provide a new way to communicate with the server. Traditional communications by a webpage is request-response: the browser sends a request for information to the server, which then sends back a response. Each request and response uses a new connection, and that connection is closed after the response is returned to the client. As you can imagine, this is a poorly performing method because of the time spent creating and closing each connection. Also, such communication cannot be two way because both client and server cannot talk simultaneously, and the server does not easily maintain a connection to the client.

WebSockets uses a different approach in that it provides duplex, or two-way, communication between the server and client. Both parties can communicate at the same time, as in chatting or instant messaging clients. It also limits connection creation and disposal so that it occurs only once rather than with every message. It is essentially a TCP-based protocol that enables two-way communication to occur over a single connection.

Source: Exam Ref 70-486- Developing ASP.NET MVC 4 Web Applications