Domain Driven Design Quickly

I just realized that it has been almost 10 years since Eric Evans wrote Domain-Driven Design: Tackling Complexity in the Heart of Software.  Although it’s not new, it is still gaining awareness  and is still very relevant.  I’ve mentioned DDD in many of my posts so I figured I needed to provide some resources.

If you are new to Domain Driven Design and want a summary instead of jumping into Eric Evans book, then Domain Driven Design Quickly is for you.  Produced by InfoQ.com, this cliff notes book provide introductions to all the fundamentals of DDD.

DDD Quickly can be downloaded free from InfoQ.

Also, while browsing InfoQ, I found an older video of Eric Evans discussing what he has learned since he wrote the book.  It’s a tad old, but still provides great insight.

CQRS: Read Model

Keep it simple.  There isn’t much of a need to go out of your way adding extra layers of abstraction.  Any data access framework or ORM you might be using will already be creating a good enough level of abstraction.  With linq (IQueryable) being implemented in NHibernate, Entity Framework, or Linq to SQL, ORM du jour, you already have your a level of abstraction to your data source.

Need to query your read model from the client? Single page application maybe?  Ok… you need one more layer.  OData to the rescue.  WCF Data Services provides an incredibly easy implementation with Entity Framework.  ASP.NET Web API does have an OData implementation but has limitations.

Keep it simple:

  • Data Source
  • Data Access Layer (ORM)
  • OData Layer – only if needed if client is making the query
  • Client