透過 Event Storming 初步捕捉 Bounded Context 與 Aggregate 後，接著我們該如何把每個 Bounded Context 以及其中的 Aggregate 轉化成開發時建模的各個 Domain Model 呢？ 而這便是 DDD Tactical (戰術) Design Pattern 要進一步帶領我們解決的問題，在 DDD Tactical (戰術) Design Pattern，根據不同的領域概念特徵分出了不同的 Pattern ，而我們將會帶各位認識其中最重要的三個元素：Tactical 的 Aggregate, Value Object, Entity，不進一步地把 Event Storming 捕捉的各個 Bounded Context 中的 Aggregate 逐步分析拆解，並根據領域的特徵轉化成三種不同的模型做搭配。

1. DDD
DDD TW 2020 Conference
Eason Kuo
v6610688@gmail.com
Facebook : Eason
Telegram : @kokokuo

2. Bounded Context Bounded Context Mapping
Bounded Context -
• (U) - (API )
• (D) (API )

3. Bounded Context Aggregate

4. DDD
DDD

5. DDD
DDD
Event Storming
Now

7. Service
Model
Service

8. A.
B. (
Reason
C. ) e04

9. A. )
C. e04
B.
1.
2. ( (Service)
Problem
Reason
3.

10. Model
Service
1.
2. Model
3.
1.
Set data to Model

11. Model
Service
1.
2. Model
3.
1.
Set data to Model
Model
Service
1. Model
2.
1.
2.
Call Model’s method
to change data state

12. Model
Anemic
Model
Service
1.
2. Model
3.
1.
Set data to Model
Domain
Model
Service
1. Model
2.
1.
2.
Call Model’s method
to change data state

13. Anemic
Model
Service
1.
2. Model
3.
1.
Set data to Model
Domain
Model
Service
1. Model
2.
1.
2.
Call Model’s method
to change data state
DDD

14. Bounded Context
ES Bounded Context Aggregate

15. Bounded Context .
2 1 ES Aggregate /
3 Domain Models
• Value Object
• Entity
• Aggregate Root
DDD DDD
3
Value Object,
Entity,
Aggregate Root

16. (Architecture)

17. DDD
•
•
•
•
•
• Clean Architecture CQRS Event
Driven, Event-Sourcing…

18. UI Layer
Application Layer
Domain Layer
Infrastructure Layer
Layer dependency

19. (DIP)
Domain ModelIEncrypter
MD5Encrypter
Infrastructure Layer
Domain Layer
<<Interface>>Domain Model
MD5Encrypter
Infrastructure Layer
Domain Layer

20. =
> Infrastructure Layer
Layer dependency
UI Layer
Domain Layer Interface
Interface Application Layer
(DIP)
•
• >

21. ) ) (
• (Onion Architecture)
• (Hexagonal Architecture)
• Clean Architecture)
• (

22. (Module)

23. (Module)
• .
app, controller, model, repository, service

24. (Module)
• )
• 3
• (
•
•

25. DDD (Module)
• DDD
DDD

26. DDD (Module)
( ) ( )
Bounded Context
Bounded Context
Aggregate

27. DDD (Module)
1.
2.
•
• Bounded Context
•
3. Domain Aggregate

28. 8
Q: BC (Bounded Contexts)

29. Miro
• … > Mindmap >

30. – 8 GO !
• Bounded Context Aggregate Miro
4
• Step1 :
• Step2 : Bounded Context
• Step3 : (e.g : API,
Application, Domain, Infrastructure)
• Step4 : Domain Aggregate
• PS: Bounded Context
Aggregate …
•

31. ES Bounded Contexts Aggregate
• BC

32. ES Aggregate
DDD

33. Domain
Model
Aggregate
Root
Entity
Value
Object
Aggregate
Event Storming DDD Tactical Modeling
• ES Aggregate
ES Aggregate

34. Domain
Model
Aggregate
Root
Entity
Value
Object
Aggregate
Event Storming DDD Tactical Modeling
Aggregate
ES
ES Aggregate v.s Aggregate
• ES Aggregate
DDD
Aggregate

35. Aggregate ( )
• Aggregate
(Entity) (Value Object)
<Entity>
Entity Value Object
Aggregate
Value Object
0…N
0…N
0…N

36. Aggregate ( )
•

37. Aggregate ( )
•

38. Aggregate ( )
•
Aggregate

39. 10
Q: Aggregate

40. Aggregate
• BC Aggregate Domain
Expert Miro
• Clue 1 Aggregate
E.g : Aggregate

41. Aggregate
• BC Aggregate Domain
Expert Miro
• Clue 2 Aggregate Read Model
E.g : Aggregate

42. Aggregate
• BC Aggregate Domain
Expert Miro
• Clue 3 Domain Expert
• Miro
E.g : Aggregate

43. – 10 GO !
• PS: Bounded Context
Aggregate …
•
• BC Aggregate Domain
Expert Miro
• Clue 1 Aggregate
• Clue 2 Aggregate Read Model
• Miro
• Clue 3 Domain Expert

44. Aggregate

45. Entity Value Object
•
Entity Value Object
Entity
Value
Object
0…N

46. Value Object

47. Aggregate Value Object ( )
Value Object

48. Value Object – / (
•
)
)

49. Value Object – )
Toyota VIOS 5
3.5 L
48 / (
1200 0989-123-383 …
… ( … / 3 /
…
/ …
• ( /

50. Value Object – )
( / 3 /
…
/
Toyota VIOS 5
… 3.5 L
48 / (
1200 0989-123-383
• / / )

51. Value Object – (
) / 3 /
/
( Toyota VIOS 5
3.5 L
48 / )
1200 0989-123-383 …
•

52. Value Object – (
•
•
• /
•
•
•
•
(VO)
•
•
(VO)
•
•
(VO)
•
•
•
(VO)
•
•
•
•
(VO)
Value Object )
Value Object

53. 10
Q: Aggregate Value Object ( )

54. Aggregate Value Object ( )
• Aggregate Value Object
Grouping.
Step 1

55. • Aggregate Value Object
Grouping.
Step 1
E.g
Aggregate Value Object ( )

56. • Aggregate Value Object
Grouping.
Step 2 : Grouping ( )
Step 3 : Grouping Value Object.
Aggregate Value Object ( )

57. – 10 GO !
• Aggregate Value Object
Grouping.
Step 1
Step 2 : Grouping ( )
Step 3 : Grouping Value Object.
Sample :

58. Aggregate Value Object
Value Object

59. Value Object –

61. Value Object )
( )

62. Value Object –
Value Object

63. Value Object –
Value Object Setter Method (immutable)
only getter

64. Value Object –

65. Value Object Value Object
/
Value Object –

66. Value Object –
•
•
•
•

67. (Entity)
Entity

68. Aggregate Entity ( )
1.
2.
4.
Entity
3.

69. Aggregate Entity ( )
• /
( )

70. Entity –
•

71. Entity –

72. Entity –
•
Entity
•
Value Object
0...N

73. Entity –
•
• (Unique ID) ?
DB ID
• (VIN)

74. Q : Entity Value Object ?
Q1 : Entity Value Object
Q2: Entity Value Object
Q3: Entity
Value Object

75. A :
Value Object Entity

76. 10
Q: Aggregate Entity ( )

77. Aggregate Entity ( )
• Aggregate Entity
Step 1
Step 2
Step 3 Value Object

78. Aggregate Entity ( )
• Aggregate Entity
Step 4 Entity

79. Aggregate Entity ( )
• Aggregate Entity
Step 5 Entity Value Object

80. – 10 Go !
• Aggregate Entity
Step 1
Step 2
Step 3 Value Object
Step 4 Entity
Step 5 Entity Value Object
Sample :

81. Aggregate Entity Value Object
Entity

82. Entity –
Ticket number
Context

83. Entity –
e.g.

84. Entity – (Unique ID)

85. Entity – Value Object
• Entity Value Object
•
• Unique ID Value Object
•
•
•

86. Entity – Model !=
Entity
Table SchemaDomain Model

87. Entity -
• - (
• ) setter
• (
•

88. Aggregate Entity Value Object
•
•
• (
•
)
•
• Getter (
• •
(Entity) (Value Object)

89. Back to Aggregate

90. Aggregate ( )
Aggregate Root
<Entity>
Entity Value Object
Aggregate
Value Object
0…N
0…N
0…N•

91. Aggregate ( )
• Business rule 0
) (
•
•
•
•
•

92. (Aggregate)

93. (Aggregate) (Aggregate Root)
•
Entity
•
• E.g: OrderItem Order
• ES (Command)
Object
Operate Aggregate Root’s Method
to access / change data state.
Object

94. (Aggregate) (Aggregate Root)
•
Entity
•
• E.g: OrderItem Order
• ES (Command)

95. (Aggregate) (Aggregate Root)
• (
)(
•
• E.g: Order OrderItem
Order > 0

96. (Aggregate) (Aggregate Root)
Entity Aggregate Aggregate Root
Entity

97. 5
Q: Entity Aggregate ( )

98. Entity Aggregate ( )
• Aggregate Entity
Aggregate Root
Step 1 Entity
Step 2
Aggregate (Aggregate Root )

99. Entity Aggregate ( )
• Aggregate Entity
Aggregate Root
Challenge Entity
Reason 1 ES Aggregate Aggregate
Reason 2 Entity Entity ? Aggregate Root
Reason 3 Entity ? Aggregate
Root

100. – 5
• Aggregate Entity
Aggregate Root
Step 1 Entity
Step 2
Aggregate (Aggregate Root )
Challenge Entity
Reason 1 ES Aggregate Aggregate
Reason 2 Entity Entity ? Aggregate Root
Reason 3 Entity ? Aggregate Root

101. (Aggregate Root)
• E.g : Order Entity Aggregate Root
• Aggregate Entity
Entity Aggregate Root
• Aggregate Entity
•
• Aggregate
• ES Aggregate (Command)
Aggregate Root
• Entity

102. Domain Model

103. Domain Model
PS:

104. Domain Model
OrderItem
Update
Update Update

105. Order 250
Tracy
Mary
Domain Model

106. Domain Model
Tracy ChickenMary Cola

107. Domain Model
Order 250

108. Domain Model
Order 250
Domain Model

109. Aggregate
1.Check Order in DB Version == 0
2.Check Total > 250
3.Update Update Order & OrderItem
Version 0: Order Total = 330.
1.Check Order in DB Version == 0 (Error)
2. Rollback
Version 1: Order Total = 270.

110. Aggregate
Transaction

111. Transaction
Aggregate

112. Aggregate Entity Value Object

113. Aggregate .
1 Domain Model 3
Domain Model 2
3 Domain Model
Aggregate Root, Entity, Value Object
Aggregate
Aggregate

114. Recap
•
• Value Object
• Entity
• DDD
• Aggregate Root Aggregate Entity, Value Object
• Aggregate ) Entity, Value Object
( )

115. Thanks your Time