leveraging more then ddd lite in the startup project
DESCRIPTION
Short presentation about how Domain Driven Design help me with my startup project. A lightweight CQRS approach was used (commands separated from queries without other ceremony).TRANSCRIPT
Points to consider
• First rapide release• Should it be dirty but fast ?• Fear of overengeeniring / overdesign• Lack of explicit domain• Lack of domain expert
What we’re exactly doing ?
Phase 1• Gather user profiles• Offer configurable visual templates• Share on social networksPhase 2• Web intelligence matching algo• Feedback collecting• Job offer recommendations
Going down the DDD path…
• We want to avoid architecture 2011 effect
What DDD could bring us ?
• Staying on the right track
What benefit DDD could bring us ?
• Staying on the right track• Explicit behavior• Discovering concepts by challenging
constantly what we know about the model• Application features are going to change often
over the years (Vaughn Vernon IDDD book)• You don’t understand the domain because it’s
new (Vaughn Vernon IDDD book)
Strategic design
• Working on the use cases from screens• Making a model• Challenging your assumptions• Starting to define UL• Code / Refactor• Iterate over the points above
CQRS… what ?
Idea behind• Separate write from readsPoints to consider• Do I need a separate data store for r/w ?• Do I need ES ?• Do I need Event Store ?• Do I need Domain Events ? (more DDD part)
UI
UI
Domain
Infrastructure CommandProc
Validation
Validation Ex: 2
Validation Ex: 3
Domain
Breaking the rule
• Rule of thumb : One aggregate state modification per transaction
UI
Infrastructure
Wrap up
What I’ve achieved• Decoupling• Maintanibility• ExtensibilityWhat bothers me• Mapping (« at boundaries, application are not
object oriented » Mark Seemann)
Proof