The ADO.NET Entity Framework is a type of ORM. It is a development platform that provides a layer of abstraction on top of the relational or logical model. In doing so, it isolates the object model of the application from the way the data is actually stored in the relational store. Developers can use the ADO.NET Entity Framework to program against an object model rather than the logical or relationship model.
This level of abstraction is achieved using the Entity Data Model (EDM)—an extended Entity Relationship Model. The EDM reduces the dependency of your domain object model on the database schema of the data store in use. We will discuss more on this topic later in this chapter.
Developers can use the ADO.NET Entity Framework to work with domain specific properties such as employee name employee address, contact details, etc, without having to be concerned with how the actual data is stored and represented in the underlying data store. The framework can take care of the necessary translations to either retrieve data from your data store, or, perform inserts, updates, and deletes.
The ADO.NET Entity Framework is an extended ORM technology from Microsoft. We say it is an extended ORM because it has many additional features compared to a typical ORM. ORMs often use metadata and factory classes to retrieve data or collections of data. On the contrary, using the Entity Framework, you can easily map your data to be accessible in a relational representation in the database to objects, no matter how the mapping is implemented. You can expose different data views to your application without having to change your relational schema. In essence, this allows the applications to have their own view of the data. The applications can even reuse the same views of data amongst themselves.
The major difference between the ADO.NET Entity Framework and ORM tools is in the Entity Data Model and the former's ability to query data using strongly typed LINQ. You can even use Entity SQL, a T-SQL like query language for querying the Entity Data Model, to execute dynamic queries. In addition to what a typical ORM framework provides, the ADO.NET Entity Framework provides and supports entity inheritance, entity composition, and a flexible, loosely coupled three tiered model consisting of the conceptual model, the mapping layer, and the storage model.
The ADO.NET Entity Framework enables you to even extend the existing schema. In other words, you can extend the generated entity classes to create your own custom entity classes. You can define relationships of any kind such as one-to-one, one-to-many, and even many-to-many. So, isn't it a better ORM?