Overview

The data may span multiple storage systems, each with its own protocols; even applications that work with a single storage system must balance the requirements of the storage system against the requirements of writing efficient and maintainable application code.
The Entity Framework enables developers to work with data in the form of domain-specific objects and properties, such as customers and customer addresses, without having to concern themselves with the underlying database tables and columns where this data is stored.
You can work at a higher level of abstraction when you deal with data, and can create and maintain data-oriented applications.

Architecture Components

The Entity Framework Data Model is described in the edmx file by three XML based languages.
- CSDL (Conceptual schema definition language) describes the application entities.
- SSDL (Storage schema definition language) describes the database schema.
- MSL (Mapping specification language) describes how the objects map to the tables and columns in the database (Link CSDL and SSDL).
**EDM (Entity Data Model):** Consist three main parts- Conceptual model, Mapping and Storage model.
- Conceptual Model: It contains the model classes and their relationships. This will be independent from your database table design.
- Storage Model: It is the database design model which includes tables, views, stored procedures and their relationships and keys.
- Mapping: Mapping consist information about how the conceptual model is mapped to storage model.
**LINQ to Entities:** It is a query language used to write queries against the object model.
- It returns entities, which are defined in the conceptual model.
**Entity SQL:** It is another query language just like LINQ to Entities.

Object Service: It is a main entry point for accessing data from the database and to return it back.
- It is responsible for materialization, which is process of converting data returned from entity client data provider to an entity object structure.
Entity Client Data Provider: The main responsibility of this layer is to convert L2E or Entity SQL queries into a SQL query which is understood by the underlying database.
- It communicates with the ADO.Net data provider which in turn sends or retrieves data from database.
ADO.Net Data Provider: This layer communicates with database using standard ADO.Net.