1. ADO.NET Entity Framework
September 22, 2018September 22, 2018
MD. SAIFULLAH AL AZAD, Software Architect
LEADS Corporation Limited
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2. What Is It?
Visual Studio 2010
.NET 4.0
LINQ
Entity Framework 4.2
The ADO.NET Entity Framework is part of Microsoft’s next generation of .NET technologies.
It is intended to make it easier and more effective for object-oriented applications to work with data.

3. SQL Server Modeling Services
Architecture
Visual Studio
“Quadrant”
Data Services
Entity Framework
ADO.NET
“M”/EDM
SQL
Azure
SQL
Server …
SQL Server Modeling Services

4. The Logical Data Model
Tables
Views
Stored Procedures
Foreign Key Relationships
Almost any business application today has to speak to a relational database.
This involves the usual suspects of tables with foreign keys, a smattering of views, and generally a gob of stored procedures.

5. The Object-Oriented Domain Model
Objects
Behavior
Properties
Inheritance
Complex Types
Applications themselves are written in a completely different world.
The same data that lives in the relational database is represented entirely differently in the application.

6. The Result
Logical Data Model
Lots of Custom Code
Application Domain
The result of this “impedance mismatch” is that developers devote a lot of time and energy writing code to translate between how the database likes to see data and how the application likes to see data.

7. Other Ways to Address The Same Problem
Hibernate (Java)
Enterprise Objects Framework (Mac OS)
NHibernate (.NET)
LINQ to SQL (Visual Studio 2008)
And many, many, more …

8. The ADO.NET Entity Framework
Logical Data Model
Entity Data Model
Less Custom Code
Application Domain
The ADO.NET Entity Framework seeks to remedy the problem by providing a layer of abstraction between the logical data model and the application domain.

9. Why the Entity Model? Logical Data Model Entity Data Model
Tables
Rows
Foreign Keys
Entity Data Model
Entity Sets
Entities
Relationships
Closer to the application problem space
Better suited for object oriented programming
Supports Inheritance
Supports complex types
Relationships are more meaningful to the application

10. The “Stuff” in ADO.NET Entity Framework
The tools and technology that developers will interact with when using the ADO.NET Entity Framework

11. Entity Data Model A gob of XML that defines
Logical Data Tables, Views, Foreign Keys
Entity Objects that Map to the Logical Data
The Mapping Between the Two

12. Entity Data Model Designer
A Visual Studio Designer that protects developers from the XML that is the EDM

13. ObjectContext
A code-generated data context created from the Entity Data Model
Responsible for managing communication between the conceptual data model and the logical data model

14. Entities
Code-generated class definitions for objects defined in the EDM.

15. Getting the Data Out
How do we get data out of the fancy Entity Data Model?

16. eSQL (Entity SQL) A brand new SQL language to learn
Leverages the rich, object-oriented Entity Data Model
Inheritance
Collections
Complex Types
Literal Strings – No Compiler Checking
Questionable value in embedded SQL in code

17. Extensions Methods and String Predicates
Queries the object model created against the EDM
Still string-based. No compiler checking
An ugly mix of code and eSQL statements

18. LINQ to Entities
Full compiler checking. No wondering if the query is valid.
A fun new SQL-Like syntax
More OO-ish

19. What Can You Do?
The power of the Entity Data Model contrasted to a logical data model of tables and stored procedures.

20. Combine Multiple Logical Tables into One Entity
Database Tables
Entity Data Model

21. Implement Inheritance
Database Tables
Entity Data Model

22. Other Fun Stuff Implement Complex Types (e.g. Address)
Consume Conceptual Model with Reporting Services and other BI Tools
Create an EDM that talks to stored procedures
Use transactions, manage concurrency, cache execution plans

23. Manipulate Data By Manipulating Objects
Database Result Desired
EDM Object Manipulation
INSERT ROW
Create new object
Add object to EDM Context
Update Context
DELETE ROW
Get instance of object from EDM Context
Ask Context to remove the object
UPDATE ROW
Update object

24. New in ADO.NET Entity Framework 4.0
Model-first development
Automatic pluralization
Foreign keys in models
POCO class support
Lazy loading
T4 Code Generation
Template customization
IObjectSet
Virtual SaveChanges
ObjectStateManager control
Self-tracking entities
SQL generation improvements
More LINQ operator support
LINQ extensibility
ExecuteStoreQuery
ExecuteStoreCommand
SPROC import improvements
Model defined functions
WPF designer integration
Code-Only development (Feature CTP)

25. ADO.NET Today App Code ADO.NET Providers Provider Specific (PL/SQL)
“SELECT * FROM CUSTOMERS”
Customers
ADO.NET Today
App Code
ADO.NET
Customers
Command
Providers
Execute
SQL Server
Oracle
Oracle
...
DataReader
Customers

26. ADO.NET Entity Framework
Conceptual Model
UKCustomer
UKPremiumCustomer
Customers
Map

27. ADO.NET Entity Framework
Provider Agnostic (ESQL)
“SELECT * FROM UKCUSTOMER”
UKCustomer
ADO.NET Entity Framework
App Code
ADO.NET
Conceptual Model
UKCustomer
UKPremiumCustomer
Map
Entity
Provider
Customers
Command
Execute
Providers*
DataReader
UKCustomer
SQL Server
Oracle
Oracle
...

28. ADO.NET Entity Framework
.NET Entity Provider (Entity SQL)
Command
Connection
Reader EF EF
Conceptual Model
Entity
relationship EF
Programming Model
Object Relational Mapping
LINQ
Store Model
(SSDL)
Entity Data Model
(CSDL)
Mapping (MSL)
Store
.NET Data Provider
V2.0
Command
Connection
Reader
Adapter

29. Mapping Examples ( 1 – Splitting )
Store
Good Customers ID
FirstName
LastName
Bad Customers
ForeName
Surname
Mapping
Customers
CustomerId
First
Last
Type
Entities
Type=“G”
Type=“B”

30. Mapping Examples ( 2 – TPH )
Store
Mapping
Entities
Customers ID
FirstName
LastName
IsPremium
Overdraft
AccountManager
Customer
CustomerId
First
Last ?
PremiumCustomer
Overdraft
AccountManager
* Framework also supports TPT

31. Mapping Examples ( 3 – View + SPs )
Store
Mapping
Entities
ClientView1
select
c.id, c.name
from
customers c
where
c.country = ‘UK’
UkCustomer
CustomerId
Name
p_DeleteUkCustomer
p_UpdateUkCustomer
p_InsertUkCustomer

32. Any Question