Entity Framework is an Object Relational Mapper (ORM) from Microsoft that lets the application's developers work with relational data as business models. It eliminates the need for most of the plumbing code that developers write (while using ADO.NET) for data access. Entity Framework provides a comprehensive, model-based system that makes the creation of a data access layer very easy for the developers by freeing them from writing similar data access code for all the domain models. The initial release of Entity Framework was Entity Framework 3.5. It was released with .NET Framework 3.5 SP1 and Visual Studio 2008 SP1. Entity Framework has evolved a lot since then, and the current version is 6.0.
Entity Framework eases the task of creating a data access layer by enabling the access of data, by representing the data as a conceptual model, that is, a set of entities and relationships. The application can perform the basic CRUD (create, read, update, and delete) operations and easily manage one-to-one, one-to-many, and many-to-many relationships between the entities.
Here are a few benefits of using Entity Framework:
The development time is reduced since the developers don't have to write all the ADO.NET plumbing code needed for data access
We can have all the data access logic written in a higher-level language such as C# rather than writing SQL queries and stored procedures
Since the database tables cannot have advanced relationships (inheritance) as the domain entities can, the business model, that is, the conceptual model can be used to suit the application domain using relationships among the entities.
The underlying data store can be replaced relatively easily if we use an ORM since all the data access logic is present in our application instead of the data layer. If an ORM is not being used, it would be comparatively difficult to do so.
Let's try to visualize the Entity Framework architecture:
From the preceding diagram, we can see that Entity Framework is written on top of the ADO.NET framework, and underneath, it is still using the ADO.NET methods and classes to perform the data operations.