This document discusses concepts related to domain-driven design including value objects, entities, identity, aggregate roots, validation, repositories, services, and domain-driven architecture. It provides examples of a student entity and domain model, discusses validatable vs invariant objects, and debates the pros and cons of including service layers. It also provides an overview of different approaches to domain-driven design bootstrapping including layering the domain, services, and data access.

1. quot;Everything should be made
as simple as possible,
but not simpler.quot;
Albert Einstein

2. Chaos

3. Order

4. Focus

5. Create a world

6. with laws

7. Be aware of the
environment

8. Basic types for the world

9. Value objects

10. Value objects
• Represents a value
• No identity
• immutable
• Equality by value

11. good example

12. ...or not

19. All the same

20. Entities
Meet Bob

21. Hi, my name is
Bob

22. I'm 32 years old

23. ...and I'm a
starshiptrooper

24. Meet bob

25. Hi, my name is
Bob too

26. I'm also 32
years old

27. ...and also a
starshiptrooper

28. Identity

29. Identity
• Combination of properties
• Personal number

30. Aggregate Root

31. Domain
Model by
Example

32. Student

33. Student
Class

34. Student
Teacher Class

35. Mayor Address
Student
Teacher Class

36. Mayor Address
Student
Teacher Class
Location Material

37. Mayor Address
Student
Teacher Class
Schema Payroll Location Material

38. Mayor Address
Student
Teacher Class
Schema Payroll Location Material

39. Mayor Address
Student
Teacher Class
Schema Payroll Location Material

40. Mayor Address
Student
Teacher Class
Schema Payroll Location Material

41. Mayor Address
Student
Teacher Class
Schema Payroll Location Material

42. Validation

43. Validation
• Validatable objects
• !invariant object

44. Validatable object
• Default ctor
• Supported by a lot of frameworks
• Flexible
• Naive

46. !Invariant object
• No default ctor, most of the time
• Nonflexible
• Strict!

48. distortion

49. Active-Passive

50. Repositories

53. Storage

57. Services
Tight, small and focused

58. Service
layer?

59. Service layers are c00l
• Support multiple application
• Your domain is in the center
of the world
• Huge enviroments
• Read DTO's
• Write command

60. Service layers are bad, mkay
• Domain logic is boxed
• Logic duplication
• No direct feedback
• Databinding support!

61. Bootstrapping

62. Overview

63. Domain

64. DB
Domain

65. DB
UI Domain

66. Service DB
Storage
UI Domain

67. Service DB
Storage
UI Domain
Logging

68. Service DB
Storage
Service
UI Domain bus
Logging

69. Service DB
Storage
Service
UI Domain bus
Logging

70. Service DB
Storage
UI
UI Service
model
Domain bus
Beheer
Logging

71. Service DB
Storage
UI
UI Service
model
WCF Domain bus
Beheer
Logging

72. Inversion of control
You only want beer

76. Learn more

83. DISCUSSION

85. You were great!
Really, I already knew it when creating this slide