The ADO.NET Entity Framework enables developers to create data access applications by programming against a conceptual application model instead of programming directly against a relational storage schema. The goal is to decrease the amount of code and maintenance required for data-oriented applications. Entity Framework applications provide the following benefits:
-
Applications can work in terms of a more application-centric conceptual model, including types with inheritance, complex members, and relationships.
-
Applications are freed from hard-coded dependencies on a particular data engine or storage schema.
-
Mappings between the conceptual model and the storage-specific schema can change without changing the application code.
-
Developers can work with a consistent application object model that can be mapped to various storage schemas, possibly implemented in different database management systems.
-
Multiple conceptual models can be mapped to a single storage schema.
-
Language-integrated query (LINQ) support provides compile-time syntax validation for queries against a conceptual model.
Entity Framework Releases and Versioning
The ADO.NET Entity Framework was first introduced as a part of the .NET Framework and Microsoft Visual Studio release. Some releases of the Entity Framework are built on top of the latest .NET Framework but are not part of the .NET Framework.
This section lists supported Entity Framework releases that are part of the .NET Framework (also referred to as core ADO.NET Entity Framework) and releases that are built on the .NET Framework.
.NET Framework 3.5 SP1
The first version of the ADO.NET Entity Framework was introduced with the .NET Framework 3.5 SP1/Visual Studio 2008 SP1 release. For more information, see ADO.NET Entity Framework and Entity Data Model Tools.
.NET Framework 4
The second version of the ADO.NET Entity Framework was included in the .NET Framework 4/Visual Studio 2010 release. This release added the functionality described in the following topic: What’s New in ADO.NET
For more information about this release, see ADO.NET Entity Framework and Entity Data Model Tools.
Entity Framework 4.1
The Entity Framework 4.1 is not part of the .NET Framework, but is built on .NET Framework 4.
This release introduces the following: DbContext API; DbContext based T4 templates; and validation features. For more information, see What’s New and Entity Framework 4.1 and 4.2.
The DbContext API is a simplified abstraction over ObjectContext and a number of other types that were included in previous releases of the ADO.NET Entity Framework. The DbContext API surface is optimized for common tasks and coding patterns. DbContext can be used with Database First, Model First, and Code First development.
Code First is a new development pattern for the ADO.NET Entity Framework and provides an alternative to the existing Database First and Model First patterns. Code First is focused around defining your model using C#/VB.NET classes, these classes can then be mapped to an existing database or be used to generate a database schema. Additional configuration can be supplied using Data Annotations or via a fluent API. For more information, see Code First related topics in the Creating and Mapping a Conceptual Model section.
The Entity Framework 4.1 (DbContext API and Code First) is available through the Microsoft Download Center and the ‘Entity Framework’ NuGet package.
You can download the localized resources for Entity Framework 4.1 on the Download Center.
Entity Framework 4.1 Update 1
Install Entity Framework 4.2 instead of using Entity Framework 4.1 Update 1. For more information see the ‘Entity Framework 4.2’ section below.
Entity Framework 4.2
The Entity Framework 4.2 is not part of the .NET Framework, but is built on .NET Framework 4.
This release is a small update to the Entity Framework 4.1 release. It includes updates to the Entity Framework 4.1 Update 1 and changes the way the Entity Framework is versioned. Starting with version 4.2, Entity Framework is moving to Semantic Versioning. Note that this versioning only affects the Entity Framework components that are built on the .NET Framework. For more information, see Entity Framework 4.2 released.
The Entity Framework 4.2 is available through the ‘Entity Framework’ NuGet package.
.NET Framework 4.5
This is the current version that is part of .NET Framework 4.5 Beta/Visual Studio 11 Beta release. This release added the functionality described in the following topic: What’s New
Entity Framework 5.0
The Entity Framework 5.0 is not part of the .NET Framework, but is built on .NET Framework 4.5. For more information, see Entity Framework 5.0.