George Lawton contacted me at the end of February to ask some questions about O/RM as he was working on a story for theserverside.net. The story has now been published, and I think George Lawton and Jack Vaughn did a good job of providing an accurate analysis of the current situation of the O/RM market for .NET.

When I received George’s email, I was quite surprised that he was inquiring about the situation that people allegedly complain about O/RMs generating quick wins in the beginning that you pay dearly for at a later stage. In his article, you can read how strongly I disagree with this myth and I was pleased to see that other people quoted in his article feel the same.

George asked us the following three questions, which I found very interesting to discuss:

• What specific features of Genome make it simpler to use, both initially and over time, than other O/RM tools?
• What have been some of the major challenges in the use of O/RM tools, and what are the ways you have gone about addressing these?
• What specific tips do you have to offer developers in getting the most out of using O/RM tools as part of the software development process?

Intrigued by his questions, I put together quite extensive replies – replies that may be of interest to others, too. Based on my answers to George, I have put together this article to outline our thoughts on the issues above and give some advice to developers who are evaluating O/RMs.

The Singleton pattern represents a very common way of using lazy initialization with resources. Textbooks usually describe the Singleton as follows:

public class SingletonClass
{
  private static SingletonClass instance;
  public static SingletonClass Instance
  {
    get {
      if (instance == null)
      {
        instance = new SingletonClass(…);
        // do some initialization logic
      }
      return instance;
    }
  }
...
}

However, as any developer quickly realizes - implementing it in this way in a multi-threaded scenario is highly error-prone: if two threads attempt to access Instance at the same time (when it hasn't been created yet), both may run inside the if block and one of the threads will override the instance created by the other. As we tried to defend ourselves against this scenario, we changed the implementation as follows:

Let’s be honest about it: getting to know Genome is a non-trivial undertaking. It may seem downright daunting. I want to share with you some of the things I did, hoping that someone might benefit from my experiences.