Posts from December 2009.

Forward engineering with MDD: A proof of concept

Hello everybody!

I want to share with you a set of videos to show what I understand when talking about Forward Engineering applied to MDD.

First of all, a legal disclaimer: my apologies for the quality of the videos and for my rusty English: I am starting to play with video editing tools and recording software so I expect to improve my recording and editing skills on the way. Anyway, I found (I hope) they have enough quality to explain the main ideas. So seeing it is totally up to you! You have been warned!  :)

Also note: see the videos in High Quality mode (HQ) in Youtube. Otherwise, details of the samples probably will not be visible.

In a previous post I introduced a sample of the code that can be generated from a very basic conceptual model. I have created three videos to show you the main steps involved.

  1. Modeling (Video 1/3). The first video uses a minimalistic class model created inside Visual Studio 2005 with Microsoft DSL Tools. The sample creates a basic blog structure in less than 5 minutes. Note that in the specification there are no technological choices (neither the types are bind to a concrete language representation).
  2. Code Generation (Video 2/3). A quick step: Selecting a code generation (selecting a target architecture), fixing the design choices offered by the code generation and pressing the red button: Generate! A full .NET Solution is generated in less than 5 seconds ready to compile.
  3. A quick code review of the generated code (Video 3/3). Finally, I am sure you have curiosity to take a look to the output code, don’t you? This third video shows a walkthrough to show:
    • DB Scripts (table creation, foreign keys, drop scripts)
    • Database creation
    • Logic layer: POCOs (Plain Old CLR objects), NHibernate mappings and a Business Service Layer with fully functional CRUD operations.

So this is it. It is a proof of concept of how fast and direct MDD tools can be starting from a minimalistic model.

When talking about using or buying modeling & code generation products my advice is:

  • Don’t use models just for documentation. They will be outdated soon or later. On the contrary, a living (generating) model is always in sync with its target application.
  • Don’t resign yourself to just using code generation of skeletons. As you just have seen the current technology allows you to generate much more.
  • Don’t be content if anyone try to sell you a model too close or tied in any way to a given target language. Today we have just generated C#, but tomorrow may be we prefer Ruby? Python?
  • Don’t resign yourself to use a tool married with a specific database. You know, technology changes faster that we usually expect.