Entity Framework

Entity Framework is a ORM(Object-Relational-Mapper) that enables .NET developers to work with relational database using domain specific objects
It eliminates the need for most of the data-access code that developers usually need to write

Entity Framework allows you to create a model by writing code or using boxes and lines in the Entity Framework Designer. Both of these approaches can be used to target an existing database or create a new database

There are Four approaches in EF

1. Code First ( to New Database)

2. Code First ( to Existing Database)

3. Model First ( to New Database)

4. Database First ( to Existing Database)

There are two major layers in an Entity Framework application:

• The modeling layer
  
• The object layer
  

The modeling layer contains three components:

• A conceptual model consisting of domain-specific entity types and relationships, based on an Entity Data Model
  
• A database schema that defines tables and relationships
  
• A mapping between the conceptual model and the database schema

 Entity Framework object layer enables you to do the following:

• Run queries against the conceptual model.
  
• Materialize data returned from the data source as objects.
  
• Track changes that were made to the objects.
  
• Propagate object changes back to the data source.
  
• Bind objects to controls.