https://cfp.devoxx.be/2017/talk/ZJX-1883/From_Brown_Field_to_Green_Field When you're rewriting an application to a new modularised & microserviced environment with several Bounded Context's and Unicorns flying around dancing and singing out loud. Then there are several approaches to migrate or synchronise the data from the dirty, old brown legacy system to your new state of the art solution. I'll present several scenario's each with their pro's and con's.

1. From
Brown Field
to
Green Field
@stijnvp

2. Stijn Vanpoucke
Technical Architect
Agile
Domain Driven Design
Modularity
Java / Open-Source

3. Every application can evolve to
a well designed DDD solution.

7. Strategies
- #1 Big Bang
- #2 Bubble Context
- #3 Synchronisation Patterns
- Event Synchronisation
- Query Synchronisation
- File-based Synchronisation
- Database Synchronisation

8. #1 Big Bang

10. bla

11. #2 Bubble Context

12. ...pen

13. Context
Bounded

14. Bounded
Context
Bounded
Context
● Different purpose?
● Different definition?
● Different semantics?
● Different attributes?
● Different behavior?
● Different constraints?
● Different usages?
● Different users?
● Different Domain Expert?
● Different Team?
● Different Code Base/Release?
● Different SLA, NFR’s?
● ...
● Same, slightly different
or totally different wording.

15. Bounded
Context
Bounded
Context
Ubiquitous Language
Better Communication between the team and the domain
experts by using the same language.

16. Bounded
Context
Bounded
Context
Ubiquitous Language
“The bigger the Bounded Context the harder it become to
have a uniform language.”

17. Aggregate
Root Entity or
Aggregate Root
Entity
Value Object
Value Object
}
● Unique identity
● Mostly mutable
● Identified by it’s attributes
● Immutable
❏ Clean
❏ Properly Tested
❏ Well Designed
❏ Behavior Rich Objects

18. #2 Bubble Context

19. Sales

20. Sales

21. Sales
Scheduling

22. Sales
Scheduling

23. Sales
Scheduling

24. Sales
Scheduling
CFP
Sponsors

25. Sales
Scheduling
CFP Sponsors

26. Sales
Scheduling
CFP
SponsorsFacilities
Location

27. Sales
Scheduling
CFP
Sponsors
Location
Facilities

28. #3 Synchronisation

29. Anti-Corruption LayerAnti-
Corruption
Layer

31. Event Synchronisation

34. Query Synchronisation

37. File-based Synchronisation

40. Database Synchronisation

42. Database Reuse Anti-Pattern

44. Thanks for listening!
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