Domain Driven Development brief overview

1. Lalit Kale e-Zest Solutions Ltd. Domain Driven Design

2. Problem

3. Problem- Characters Involved

4. Problem Diverse Characters to solve one problem Everybody talks in different language Ultimate Result- Delivered solution is brittle and Fragile

5. Everybody who are involved should talk in one Language Step 1 : Agree on language terminology and definitions Step 2: Call on the language expert Step 3 : Use Business model to device the language Solution

6. Domain: “Afield of study that defines a set of common requirements, terminology, and functionality for any software program constructed to solve a problem in that field “. Driven: Focused on Domain Driven Development

7. Domain: “Afield of study that defines a set of common requirements, terminology, and functionality for any software program constructed to solve a problem in that field “. = Problem Domain Domain Model: The domain model is a rigorously organized and selective abstractionsof knowledge’ Domain Driven Development

8. Traditional Architecture Presentation Business Layer Infrastructure/ Utility/Library Data Access (DAL)

9. DDD Architecture User Interface Application Services M Domain Services Database Domain Model Services File system Tests Infrastructure etc

10. DDD Architecture User Interface Application Services M Domain Services Database Domain Model Services File system Tests Infrastructure etc

12. Ubiquitous Language

13. Bounded Contexts

14. Persistence Ignorance

15. Refactoring

16. Command Query Separation (CQS)

17. When to use DDD

18. When NOT to Use DDD

19. Patterns

20. Entities

21. Value Objects

22. Aggregate Roots

23. Object Creation Patterns

24. Repository

25. Specification

26. Domain Services

27. Modules

28. Domain Events

30. DDD Fundamentals-Entity Objects that have a distinct identity that runs through time and different representations. You also hear these called "reference objects". Entities are usually big things like

31. DDD Fundamentals-Value Objects A small simple object, like money or a date range, whose equality isn't based on identity. Value Objects are usually small things (Hidden concepts in system) like

32. DDD Fundamentals- Aggregate Roots An Aggregate comprises of an intimately associated group of Entities and Value Objects Aggregates are treated as a single unit for the purpose of persistence, and references are only allowed to the Aggregate Root

33. DDD In Practice

34. Without DDD

35. With DDD-Code Flows

36. Promotes high cohesion and low coupling Easy to test domain components Business (domain) logic is isolated from non-domain and infrastructure code Adding/changing services does not influence the domain or other services. Everybody talks on same terms Advantages