Entity Framework 

First question that comes to the mind is what is an entity framework? 

So let’s see standard definition of Entity Framework given by Microsoft:

The Microsoft ADO.NET Entity Framework is an Object/Relational Mapping (ORM) framework that enables developers to work with relational data as domain-specific objects, eliminating the need for most of the data access plumbing code that developers usually need to write. Using the Entity Framework, developers issue queries using LINQ, then retrieve and manipulate data as strongly typed objects.

To simply say it: Entity framework is an Object/Relational Mapping (O/RM) framework. It is an enhancement to ADO.NET that gives developers an automated mechanism for accessing & storing the data in the database and working with the results in addition to DataReader and DataSet.

Now the question is what is O/RM framework and why do we need it? 

ORM is a tool for storing data from domain objects to relational database like MS SQL Server in an automated way without much programming. O/RM includes three main parts: Domain class objects, Relational database objects and Mapping information on how domain objects maps to relational database objects (tables, views & storedprocedures). ORM helps us to keep our database design separate from our domain class design. This makes application maintainable and extendable. It also automates standard CRUD operation (Create, Read, Update & Delete) so developer doesn’t need to write it manually.

There are many ORM frameworks for .net in the market like DataObjects.Net, NHibernate, OpenAccess, SubSonic etc. ADO.NET Entity Framework is from Microsoft.

Entity Framework vs LINQ-to-SQL:

You may think that what is the difference between Entity Framework and LINQ to SQL which does that same thing. There are some differences between Entity Framework and L2S.

• Entity framework has a full provider model. It supports not only SQL Server but also other database like Oracle, DB2, MySQL etc.


• Most of the time L2S classes must be one-to-one with database objects e.g. Customer class can be mapped only with Customer table. Where as in Entity Framework you can map your domain class with multiple tables using various inheritance strategies like table per type (class) or table per hierarchy of classes etc.


• You can have multiple modeling techniques using Entity Framework 4.1 like code first, model first or database first.


• Microsoft has long term strategy to support and integrate Entity Framework with multiple Microsoft products.