Building N Tier Applications With Entity Framework Services 2010

Building nTier Applications with Entity Framework Services

Agenda

Overview

nTier Architecture Overview
Model to create flexible reusable applications
Only need to modify or add layers instead of rewriting entire applications over

Where’s Your Data Model?
Applications Today…
Implicitly Contain the Data Model
Logic and Model Intertwined
Conceptual Mismatch
Often encapsulate in a "Data Access Layer"

Where’s Your Data Model?
What Is Really Needed
Applications work with a well Defined Model
Storage Schema Abstraction
Declarative mapping between application and storage models
No brittle, hard-coded mapping

Entity Framework

Object Relational Mapping
What is ORM?
Technique for working with relational tables as if they were objects in memory
Intention is to hide away the complexity of the underlying tables and give a uniform way of working with data
Why use ORM?
Productivity
Retain database independence
ObjectsClassesEntities

Object Relational Mapping
There are many ORMs for .NET developers already in existence. E.g.
LLBLGen Pro http://www.llblgen.com/
Nhibernate http://www.hibernate.org/343.html
EntitySpaces http://www.entityspaces.net/Portal/Default.aspx

The Microsoft Entity Data Model
An extended relational model with Entity-Relationship Model concepts
Entity Types
Strong type with Identity
Inheritance
Scalar/Complex properties
EntitySets
Hold instances of Entity Types
Similar to relational tables
Can have multiple Entitysets of the same EntityTypes
Relationships ("Associations")
Named relationships between Entities
0..1:*, 0..1:0..1, 1:1, 1:M, M:N
Navigation may be exposed as NavigationProperties on EntityTypes
AssociationSets
Contains instances of associations
May be queried directly
EntityContainers
Contains EntitySets, AssociationSets
SalesPerson
EmployeeID = 294272LoginID = adamTitle = "Dev Lead"VacationHours = 0…
Manager
1
1
N
Reports
SalesPerson
SalesPerson
EmployeeID = 729742LoginID = peteTitle = "Developer"VacationHours = 0…ExpenseAccount = …CarLicenseNum = ……
SalesPerson
EmployeeID = 729742LoginID = peteTitle = "Developer"VacationHours = 0…ExpenseAccount = …CarLicenseNum = ……
EmployeeID = 729742LoginID = peteTitle = "Developer"VacationHours = 0…ExpenseAccount = true…

EDM & Entity Framework?
The Entity Framework (EF) is an Object Relational Modeling tool leveraging the EDM
Focus on your domain, not how to persist!
EDM is used to describe your model.
Allows different rate of change between database and code!
EF uses a storage model and mapping to enable this.

ADO.NET Entity Framework

EF Providers in Progress

LINQ to Entities – Lots of Topics

Using Entity Framework with ASP.NET

Pain Points in v3.5 SP1
Pluralization/ Singularization
Foreign Keys
Model First
Lazy Loading
Additional LINQ Operators
L2S Features & Patterns
SQL Gen Improvements

Entity Framework in .NET 4
Improvements:
Model First
T4 Templates to control code generation
Supporting DDD approach with POCO
Persistence Ignorance
Repository pattern
Query Improvements
Lazy Loading
Disconnected API’s to enable N-tier

Easily Expose Your Entities
WCF Data Services

Data Services Overview
Extends Windows Communication Foundation
Functionality
CRUD access to data over RESTful web services
Built-in URI-based query syntax
Client-side libraries for .NET and AJAX clients

Data Services
HTTP
Open Data Protocol
Hosting/HTTP Listener
Data Services Runtime
IQueryable/IEnumerable
[+ IUpdatable]
Data Access Layer
Entity Framework
Custom LINQ Provider
Relational database
Other sources

Data Services - A REST Interface
The underlying model
Entities and associations  resources and links

WCF 4
Programming Model
Core Services
Web HTTP Services
Data Services
RIA Services
Workflow Services
Service Model
Data Contract
Service Contract
Service Behavior
Channel Model
Formats
(Atom, JSON, XML,…)
Transports
(HTTP, TCP, …)
Protocols
(SOAP, HTTP, Open Data Protocol,…)

URL Conventions
Addressing entities and sets
Presentation options

Modern Data-Driven Web Apps
AJAX integration
AJAX-friendly JSON format in services
Javascript library that integrates with the ASP.NET AJAX toolkit
Silverlight support
.NET programming model for data services
Object based, LINQ enabled API
Code-gen entity types from metadata

"Traditional" Applications
Web applications
Data services client can be used in ASP.NET
ASP.NET data source control for accessing remote services
Desktop applications
Fully-featured .NET client library
Same API in desktop and Silverlight environments

What’s New in .NET 4
Data Binding
New DataServiceCollection class provides simplified binding of data service data to (WPF) controls. Includes auto updating.
Counting Entities in an Set
$count - total number of resources returned by a URI
$inlinecount - total resource count together with the resource data
Server-driven Paging
Service can be configured to return requested resources as a set of paged responses

What’s New in .NET 4
Query Projections
Query results can be modified to include only a subset of properties by using the new $select query option.
Custom Data Service Providers
Can implement a set of new data service provider interfaces, you can use various types of data with a data service, even when the data model changes during execution.
Streaming of Binary Resources
This enables you to retrieve and save binary large object data independent of the entity to which it belongs.

Summary

Conclusion

Before You Begin…
What I Have Learned So Far About The Entity Framework and ADO.NET Data Services
http://dotnettips.com/2008/09/30/WhatIHaveLearnedSoFarAboutTheEntityFrameworkAndADONETDataServices.aspx
*Part 2 coming out soon!
Using Microsoft ADO.NET Data Services
http://msdn.microsoft.com/en-us/library/cc907912.aspx

Resources
ADO.NET Team Blog
http://blogs.msdn.com/adonet/default.aspx
EF Design Blog
blogs.msdn.com/efdesign
Visual Studio Data Blog
http://blogs.msdn.com/vsdata/
dnrTV!
http://shrinkster.com/1734

Resources
Dan Simmons Blog
http://blogs.msdn.com/dsimmons/
MSDN Code Gallery
WCF Data Services Learning Guide:
http://msdn.microsoft.com/en-us/data/bb931106.aspx
WCF Data Services Team Blog
http://blogs.msdn.com/astoriateam/default.aspx

Required Book!

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Building N Tier Applications With Entity Framework Services 2010

by David McCarter on Mar 18, 2010

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Building N Tier Applications With Entity Framework Services 2010 — Presentation Transcript