avatarharuki zaemon

Domain Driven Design

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I spent many years writing software that was essentially procedural in nature with transaction scripts accessing a database through very simple active records. Since I’ve come to appreciate the benefits of a rich domain model I’ve wished I had the ability to communicate this to others.

So I was excited when I heard about the book Domain Driven Design.

It’s nicely written. A good mix of code, diagrams, anocdotes and I particularly like the transcripts of conversations from actual modelling and design sessions. Lots of examples, rules of thumb and hints and tips here and there. It reminds me of Pragmatic Programmer in the way it reads.

Points I’ve particularly liked:

  • Model-driven design he says “discards the dichotomy of analysis model and design to search out a single model that serves both purposes.” Something I’ve always felt since reading Analysis Patterns. As the author points out, this is very hard to do but well worth the effort.
  • The good old manufacturing metaphor where highly skilled engineers design and less skilled laborers assemble the products has “messed up a lot of projects for one simple reason – software development is all design.” All right! Rock on! I’m printing that out in 70pt font and sticking it up on the wall of my favourite enterprise architects office!
  • “If an unsophisticated team with a simple project decides to try a MODEL-DRIVEN DESIGN with LAYERED ARCHITECTURE, it will face a difficult learning curve.” I’ve recently pondered this as I’ve struggled with bringing teams of developers up to speed with these concepts. I’ve wondered whether I may be making matters worse before they, hopefully, get better.

Things I’ve disliked:

  • As Doug points out in his review, I too was a bit surprised by the “Manager” classes. Seems to defeat the whole purpose of rich domain models but as I haven’t finished yet and, the author promises to address this later in the book (fingers crossed) I’ve chosen to ignore it so far.
  • The book is rather verbose I’m sad to say. I got into the first section and started to stall! It was very hard to get motivated to read the rest of the book.

All in all not a bade book. Someone definitely needed to write about it but as I mentioned, it was a little verbose for my liking. But I did finish it and I’d have to say that it was probably worth it.