Uploaded byJulie Lerman
Entity Framework and Domain Driven Design
The document discusses the integration of Domain-Driven Design (DDD) with Entity Framework (EF), emphasizing the importance of focusing on business problems rather than just persistence models. It highlights concepts such as value objects, repositories, and testing practices when using EF, along with various approaches to structuring data models. Additionally, it offers resources for further learning about DDD and EF, reflecting the author's expertise in the subject.
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Entity Framework and Domain Driven Design
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- 3. D is forDomain not Persistence
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- 6. Separation of Concerns MaintainableAdaptable Testable Extensible Organized
- 7. *** Driven Development BusinessProblemSoftware Solution Code OCD
- 8. Business/Domain Layer Repository/Unit ofWork Infrastructure/Data Model ORM/Entity Framework Database UI Service Layer LINQ Tests Tests
- 9. Domain Models Services Data LayerRepositories Domain Events Infrastructure
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- 11. DDD Bounded Contexts forApplication Subsystems Customer Service Order Taking Billing Returns Marketing Human Resources Shipping
- 12. Focused DbContexts Products Promotions Customers SalesPeople Employees SalaryHistory Returns Orders Customers Payments Orders Customers Customer Service Orders Customers Billing Returns Marketing HumanResources Shipments Shippers Shipping Orders DB DB Order Taking
- 13. Focused DbContexts Products Promotions SalesPeople Employees SalaryHistory Returns Orders Payments Orders Customer Service Orders Billing Returns Marketing HumanResources Shipments Shippers Shipping Orders Customers Customers Customers Customers Order Taking DB DB
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- 16. DDD is forsolving Complex Problems. Quite often, CRUD is enough
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- 18. EF & DDDValue Objects EF Complex Types • No Identity Key • Property of Entity/other Complex Type • Maps to columns of parent entity/entities DDD Value Object • No Identity Key • Immutable • Equality compares all values • No Side-Effects
- 19. Do You Needa Persistence Model? Entity Framework/Queries/Commands Domain Model Persistence Model Payments Invoices Customers DB Mappings, DB concerns, Follow EF rules Domain Model Payments Credit Invoice Payee Payments Credit Invoice Payee Credits
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- 23. Testing with EFin the Mix • EF only or Database? • Using database: DropCreateDatabaseAlways Integration/ Tests • No EF involved: Inconsequential • EF in the way: Abstraction/Interfaces Unit Tests
- 24. Replace EF Behaviorin Tests Mocking Frameworks • Learning Curve • Magic • DbSets are not always supported Roll Your Own Fakes • Learning Curve • More coding effort • Educational EF6 More Easily Supports Mocks • DbSet has new features • Chose not to enhance IDbSet to match • Instead, DbSet is more mockable • Protected constructor has no ties to DbContext
- 25. DDD += EF •Focus on Domain • Map to persistence later • EF can resolve most DDD patterns • Some tweaks may be required • Consider separate persistence model in more complex scenarios
- 27. Coming Soon Domain DrivenDesign course
- 28. Resources • Coding forDomain-Driven Design: Tips for Data-Focused Devs Part 1-3 MSDN Mag Data Points Column August 2013, Sept 2013, October 2013 • Pluralsight On-Demand Training: pluralsight.com • MSDN Developer Center: msdn.com/data/ef • EF Team: blogs.msdn.com/adonet • LearnEntityFramework.com • Programming Entity Framework: DbContext • by Julie Lerman and Rowan Miller, O’Reilly Media, Feb 22 2012 • Domain Driven Design By Eric Evans, Addison-Wesley, 2004 • Implementing Domain Driven Design, A-W, Vaughn Vernon, 2013 • domaindrivendesign.org
- 29. consultant/mentor Microsoft MVP, INETASpeaker, ASPInsider, MCP, VTdotNET Leader contact jlerman@theDataFarm.com www.thedatafarm.com blog theDataFarm.com/blog twitter @julielerman book web site LearnEntityFramework.com Contact Info (40% off at O’Reilly booth)
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Editor's Notes
- #9 Focus on repo on this slide, then use code samples to quickly show difference between code that uses context directly and code that uses a repository, also show unit of work encapsulating a transaction possibly sharing reposPoints to make about demo ware…controller has direct access to /dependeny on EF. Need to know ins and outs of EF, linq to EF etc to get and update the data you want. Changes to data access logic may have direct impact on controller code which then needs to be modified. That may impact the UI code. That’s just the beginning of the problems.