Lerman Vvs13 Entity Framework 4 And Wcf

VVS13:WCF + Entity Frameworkin Visual Studio 2010
Julie Lerman
www.thedatafarm.com
jlerman@thedatafarm.com
twitter @JulieLermanVT

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
New Features in EF that help with n-tier
POCO Support
Foreign Keys
State methods
Serialization improvement
Custom WCF Services
Self-Tracking Entities

EFv1 and N-Tier
EntityObjects are ugly when serialized
Transferring to & from DTOs is painful
No change-tracking in the objects
Difficult & unsatisfying WCF patterns

Basic POCO Support in EF4
Turn off code generation from EDMX
“Convention” will auto-map classes/entities

Additional POCO Features
Change Tracking
By Snapshot or Proxy
Lazy Loading
By Proxy
Code Only Design
No Physical Model
Convention and Configuration

Simpler Code Gen Customization
T4
Text Template Transformation Toolkit

New State Methods Support N-Tier
ApplyCurrentValues
ApplyOriginalValues
ChangeState
ChangeRelationshipState
Used when there are no foreign keys

Change State w ApplyCurrentValues
Client Requests
Object
Service queries db/cache &returns object
fName: Julie
lName: Lerman
Client User Edits Object & returns to service
fName: Julie
lName: Flynn
Service queries db/cache for original object
fName: Julie
fName: Julie
lName: Lerman
Service updates original object with values from client
lName: Flynn
SaveChanges
ApplyCurrentValues

Foreign Key Support
Arrived in Beta 2
Default with new models
Simplifies relationship management

Basic Pattern for WCF in EF4
Use POCO entity classes
Include a State property in the classes
Return graphs
Attach returned data to new context
Fix up context state using POCO state
If not using FKs
Fix up relationships with help from db data

Self-Tracking Entities
Special API in Feature CTP
POCO Classes with state information
Special method to apply changes to an entire graph
Magically takes care of change tracking
Written for WCF and DataContract Serialization
Does not apply to ASP.NET, etc.

Summary
WCF was painful in EF version 1
Many improvements in EF4 to help n-Tier
Writing custom WCF gets much easier
Self-Tracking Entities are a good out of the box solution
Don’t forget about ADO.NET Data Services and RIA Services as well

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..
Rowan Miller (romiller.com) (EF Team)
WCF EF POCO demo with unit tests
Danny Simmons’ Aug 2009 MSDN Mag
MS PAG: Data Access Guidance
dataguidance.codeplex.com

Lerman Vvs13 Entity Framework 4 And Wcf

by Julie Lerman on Nov 21, 2009

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Lerman Vvs13 Entity Framework 4 And Wcf — Presentation Transcript