Lerman Adx303 Entity Framework 4 In Aspnet

ADX303:Options for Building ASP.NET Web Sites with Entity Framework
Julie Lerman
www.thedatafarm.com
jlerman@thedatafarm.com

Julie Lerman
website
theDataFarm.com
blog & twitter
theDataFarm.com/blog@julielermanVT
book web site
LearnEntityFramework.com
consultant/mentor
Microsoft MVP, INETA Speaker,ASPInsider, MCP, VTdotNET Leader

Agenda
Architectural Challenges
EntityDataSource
Dynamic Data
ASP.NET MVC
ObjectDataSource
Architected n-Tier Web Forms

SaveChanges Creates db Commands

Change Tracking Across Tiers
ObjectContext
ObjectStateEntry
SO1 EntityKey Original ValuesCurrent Values Other ∆ Info
ObjectStateEntry
SO2 EntityKeyOriginal ValuesCurrent ValuesOther ∆ Info
detach
entities
ObjectStateEntry
LIA EntityKeyOriginal ValuesCurrent ValuesOther ∆ Info
Original Property Values
EntityState Values
ObjectStateEntry
LIB EntityKeyOriginal ValuesCurrent ValuesOther ∆ Info

SaveChanges Fails Across Post Backs
Page Request
Post Back #1
Post Back #2
New Page Class
New Page Class
New Page Class
Create New ObjectContext
Create NewObjectContext
Create NewObjectContext
Get Entities
Process Request
Get Entities
Build HTML using Data & ASP.NET Markup
Destroy Page and Dependents

The ASP.net Spectrum with EF
Dynamic Data forEntities
ObjectDataSource
EntityDataSource
MVC
ADO.NET
Data
Services
Dev
WCF
n-Tier
Architect

EF4 Changes to the Rescue
Foreign Keys
Big help for data-binding related objects
POCO Classes & T4 Generation
State Methods
ApplyCurrentValues, ApplyOriginalValues
ChangeState
ChangeRelationshipState (when no FKs)

EntityDataSource Control

Dynamic Data Controls

ASP.NET Model View Controller
MVC Pattern using Entities as the model
MVC Goal
Separation of concerns
Testable
Entities as “Model”
EF4’s POCO entities for better separation

ObjectDataSource Control

Classes
EF Classes in a Repository
System.Data.Entity
Mock
ObjectSet
Mock
Context A
EDM &
ObjectContext(Repository A)
Mock
Context B
Queries
(Repository B)
UI
Tests
Julie Lerman Oredev 2009

Basic Pattern for ASP.NET n-Tier
Code Behind
ASPX
Business Logic
MVC View
Repository
Queries
CacheEntityKeys, Scalars (inc FKs)
MVC Controller
Model &
ObjectContext
Foreign Keys make this
approach a possibility

N-Tier ASP.NET
Serious challenges in EFv1
Help in EF4
POCO objects & T4 Code Generation
Caching gets simpler
Foreign Keys
New n-Tier methods
ChangeState, ApplyCurrentValues, ApplyOriginalValues, ChangeRelationship

Caching Considerations
SessionStatevsViewStatevs Cache
Cache with Velocity or MemCached
Cache vs Refresh from DB for Updates?
Roll your own? Use a provider?
Anyway you go – it’s still HARD

Summary
ASP.NET provides many ways to use EF
New EF4 features expand possibilities
RAD: Dynamic Data & EntityDataSource
Business Layer “Lite”: ObjectDataSource
MVC Benefits from POCOs
Web Forms n-Tier helped by Foreign Keys

Julie Lerman
website
theDataFarm.com
blog & twitter
theDataFarm.com/blog@julielermanVT
book web site
LearnEntityFramework.com
consultant/mentor
Microsoft MVP, INETA Speaker,ASPInsider, MCP, VTdotNET Leader

Resources
EF Team Blogs (blogs.msdn.com/)
adonet, efdesign, dsimmons, adjames, more..
Danny Simmons’ Aug 2009 MSDN Mag
MS PAG: Data Access Guidance
dataguidance.codeplex.com

Lerman Adx303 Entity Framework 4 In Aspnet

by Julie Lerman on Nov 21, 2009

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Lerman Adx303 Entity Framework 4 In Aspnet — Presentation Transcript