2 Architectural Concerns for Object/Relational Mappers (O/R-M) with Examples in NHibernate Jeffrey Palermo Chief Technology Officer Headspring Systems, LP Session Code: ARC401

3 Architecture? What type are we speaking of? - Application architecture - Enterprise applications (lots of code) level

4 Top Concerns for O/R Mappers Compatibility Loose Coupling Testing Changing Schema Reporting Mapping Boundaries

5 Audience Participation Raise your hand if you are using the same data access method that you were 1 year ago.

6 2 Years

7 3 Years

8 4 Years

9 5 Years

10 6 Years

11 7 Years

12 8 Years

13 9 Years

14 10 Years

15 How will you switch to the next thing?

16 Compatibility

17 OBJECT / relational mapping

18

19 Loose Coupling

20 Traditional Layered Architecture Data Business Logic UI Infrastructure

21 Web Service File Solution Structure Client Business Logic Data Access DB Infrastructure

22 Layered Onion Architecture Domain Model Domain Services Application Services User Interface Infrastructure Tests DB Web Service File Application Core

23 Web Service File Solution Structure Client Core Infrastructure DB IoC Container

24 Loose Coupling (loose coupling means no project reference)

25 Testing

26 Testing (I can test anything it if has well-defined boundaries)

27 Testing

28 Testing Data Access Local database Test setup Test execution Test teardown Automate, Automate, Automate

29 Testing (I can test anything it if has well-defined boundaries)

30 Changing Schema

Table Per Type Mapping..

Table Per Hierarchy Mapping

33 Table Per Type Mapping

34 Table Per Hierarchy Mapping

35 Changing Schema

36 Reporting

37 Mapping Boundaries

38

39 Mapping tips Use collection mappings only where necessary Leverage component mappings Keep database details in the database Don’t expose collections as properties (do you support collection.Clear())?

40 Use any good O/R Mapper Keep it behind interfaces Application logic and business objects shouldn’t depend on ORM

41

Related Content Interactive Theater Sessions WUX08-TLC TDD, DI, and Other Acronyms with ASP.NET MVC Friday, 1PM-2:15PM

43 About me CTO, Headspring Systems Software management consultant Agile coach MCSD.Net Microsft MVP, ASPInsider Certified ScrumMaster Director, Austin.Net User Group Board member, AgileAustin INETA speakers bureau U.S. Army Veteran Party with Palermo Agile Boot Camp:

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