Intro into CQRS and Event Sourcing

Transcript

1. Intro to Command Query Responsibility Segregation (CQRS) Event Sourcing (ES) Alex Peta alex@alexpeta.ro @alexpeta | http://github.com/alexpeta
2. Summary “The Problem” Intro to CQRS CQRS / ES CODE ( ASP MVC) Q & A
3. 1. "The Problem" CRUD model
9. Issues ◦ Making changes becomes harder and harder. ◦ Transactions become harder. ◦ A lot of "technical" work that the business has to pay for ◦ Testing can become an "engineering discipline" ◦ All or nothing ◦ Bigger size , more complexity ◦ Increase knowledge requirements ◦ Difficult to scale, difficult to version
10. 2. Intro into CQRS There is debate to what it actually is: ◦ Is it a pattern? ◦ Is it an approach? ◦ Is it a framework? ◦ Is it a architecture?
11. CQRS = separate models and reads and writes Command Query Responsibility Segregation An architectural pattern : ◦ separate commands that change state ◦ from queries that read state
12. Simplify
15. CQRS / ES
16. CQRS - Common Data Different API
17. CQRS - Separate Data
18. CQRS - Event Sourcing
19. 3. CODE
20. When To Use CQRS Collaborative domains where multiple operations are performed in parallel on the same data. Scenarios where performance of data reads must be fine-tuned separately from performance of data writes, especially the read/write ratio is very high. Scenarios where the system is expected to evolve over time and may contain multiple versions of the model, or where business rules change regularly.
21. When not to use CQRS Where the domain or the business rules are simple. Where a simple CRUD-style user interface and the related data access operations are sufficient. For implementation across the whole system
22. 4. Q & A
23. References Microsoft Patterns & Practices : https://msdn.microsoft.com/en-us/library/dn568103.aspx Channel 9 : https://channel9.msdn.com/Search?term=CQRS#ch9Search http://channel9.msdn.com/Events/aspConf/aspConf/CQRS-with-ASP-NET-MVC-A-Year-On
25. Slides Code