Practical Domain-Driven Design with EF Core - NDC London 2021

Practical Domain-Driven Design With EF Core Hossam Barakat Technical Lead
at Willow @hossambarakat_ | www.hossambarakat.net

@hossambarakat_ What is Domain-Driven Design? “Domain-Driven Design is an approach
to software development that centers the development on programming a domain model that has a rich understanding of the processes and rules of a domain. ” -- Martin Fowler

@hossambarakat_ What is Domain Model? “An object model of the
domain that incorporates both behavior and data. ” - Martin Fowler “A system of abstractions that describes selected aspects of a domain and can be used to solve problems related to that domain. ” -- Eric Evans

@hossambarakat_ Strategic Design

@hossambarakat_ Bounded Contexts • A defined part of software where
particular terms, definitions and rules apply in a consistent way • Clear boundaries between different parts of the system https://martinfowler.com/bliki/BoundedContext.html

@hossambarakat_ Focus on the Core Domain

@hossambarakat_ Inside the Core Domain

@hossambarakat_ How to apply DDD to my legacy codebase?

@hossambarakat_ Sample Domain

@hossambarakat_ Domain Model

@hossambarakat_ Demo

@hossambarakat_ Extract Methods

@hossambarakat_ Avoid Public Setters

@hossambarakat_ Encapsulate Behavior in Domain Model

@hossambarakat_ Encapsulate Collection

@hossambarakat_ Encapsulate Behavior in Domain Model

@hossambarakat_ Encapsulate Behavior in Domain Service

@hossambarakat_ Double Dispatch

@hossambarakat_ Domain Events Entity Domain Events DBContext SaveChanges() Event Handler
Handle() Event Handler Handle() Event Handler Handle() Mediator Publish() Action() SaveChangesInterceptor SavingChanges()

@hossambarakat_ From Primitive Obsession to Value Objects

@hossambarakat_ Where is the Repository?

@hossambarakat_ Can the Unit of Work help us?

@hossambarakat_ Embrace the DbContext

@hossambarakat_ What about custom queries? • Query classes • Specification
pattern • Extension Methods

@hossambarakat_ Specification: Current Query

@hossambarakat_ Specification: Base Classes

@hossambarakat_ Specification: Concrete Sample

@hossambarakat_ Specification: Extension Methods

@hossambarakat_ Base Entity ID

@hossambarakat_ Resources • https://github.com/hossambarakat/Subscriptions-DDD • https://github.com/ardalis/Specification

@hossambarakat_ Questions

@hossambarakat_ Thanks Hossam Barakat Tech Lead at Willow @HossamBarakat_

Practical Domain-Driven Design with EF Core - N...

Practical Domain-Driven Design with EF Core - NDC London 2021

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