Entity Framework

Eyal VardiCEO E4D Solutions LTDMicrosoft MVP Visual C#blog: www.eVardi.com

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Agenda

Data Access History

OO vs. Relational World

EF Architecture

Development Approaches

EF 4.0+ New API

EDM

Conceptual Model

Mapping

StorageModelADO.NET Provider

Entity Client Provider

Object Services

LINQ to Entities

Entity SQL

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Data Access History

2003 - DataSet & DbCommand

2005 – DataSet &Table

Adapters

2008 – LINQ to SQLEF 1.0

2010 - EF 4.0

2011 - EF 4.1

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Entity Framework Flow

LINQ Query Objects SubmitChanges()

SQL Query Rows SQL or Stored Procs

Entity Framework

SQLServer

from c in db.Customerswhere c.City == "London"select new { c.Name, c.Phone }

select Name, Phonefrom customerswhere city = 'London'

Application

Services:- Change tracking- Concurrency control- Object identity

EDMX

ADO.NET Provider

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OO vs. Relational World

Data Types

Associations

Granularity

Inheritance

Identity

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EF Architecture

EDM

Conceptual Model

Mapping

StorageModel

SQLServer

ADO.NET Provider

Entity Client Provider

Object Services

LINQ to Entities Entity SQL

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Entity Data Model (EDM)

The EDM is the link between the model and the database.

The EDM is that it decouples your application from the underlying store.

Entity Data Model (EDM)

Conceptual Model (CSDL)

Mapping(MSL)

StorageModel(SSDL)

Storage

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Object Services

Materialization The process of transforming the data obtained from the

Entity Client data provider, which has a tabular structure, into objects.

Change tracking Tracks any changes made to the objects.

Query transformation Translates queries it into a command tree that’s then passed

on to the underlying Entity Client.

Object identities

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Object Services Functions

Querying Querying data as objects Shaping query results Composing queries CRUD Lazy loading Inheritance Navigating relationship

Change tracking Saving changes Attaching objects Detaching objects Serializing objects

Managing Object identities Concurrency Transactions

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Entity SQL & LINQ to Entities

LINQ to Entities - The LINQ dialect that enables typed queries against the model.

Entity SQL - The second way of querying the object model. Entity SQL is string-based. Can be used to retrieve data at low level, directly using the

Entity Client.

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Development Approaches

EDM

Conceptual Model

Mapping

StorageModelADO.NET Provider

Entity Client Provider

Object Services

LINQ to Entities

Entity SQL

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Database First If you already have a database, the Entity

Framework can automatically generate a data

model that consists of classes and properties

that correspond to existing database objects

such as tables and columns.

DB

GeneratedData Model

(.edmx)Database First

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Model First If you don't yet have a database, you can

begin by creating a model using the Entity

Framework designer in Visual Studio.

The designer can generate DDL (data definition language)

statements to create the database.

Generated

DB

Data Model(.edmx)

Model First

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DB

GeneratedData Model(Classes)

Code First

Code First Whether you have an existing database or not, you

can code your own classes and properties that correspond to tables and columns and use them with the Entity Framework without an .edmx file.

Generated

DB

Data Model(Classes)

Code First

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Why DbContext & DbSet? This API provides a more productive surface

for working with the EF and can be used with the Code First, Database First, and Model First approaches.

Model Discovery

Model Caching

DbSet Initialization

Database Provisioning

* More info click here

DbModel Constructor

ObjectContext Constructor

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EF 4.1 New API

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Features That Are Not Supported

features are not supported by the DbContext API. To use these features, use the ObjectContext API.

Compiled queries

MEST (Multiple Entity Sets per Type)

Self-tracking entities. To use the DbContext API in an N-tier application,

consider using WCF Data Services or RIA Services.