NHibernate is one of the most useful and complicated open-source projects in the .NET community. Some consider NHibernate prohibitively difficult. It can be quite difficult and frustrating, especially when you only want to use it to build a simple, prototype, or startup-size web site. That's where NHQS fits in.
This evening I was finally able to get the NHQS library up on NuGet. As always, you can use either the NuGet package explorer or the command-line tool to grab yourself NHQS.
Most of the previous posts have alluded to the multiple-database goal of NHQS and some of the code has demonstrated the beginnings of a demonstration of the feature. This post will take a longer look at how NHQS can provide multiple-database support and will wrap up by demonstrating transaction management within NHQS.
Though this might be the poorliest-named aspect of NHQS it is my favorite part, for it takes a huge part of the complexities associated with NHibernate and makes them simple. Dirt simple. Like, “you’re kidding, right? That couldn’t possibly work,” simple.
As explained in various posts all over the internet (like this one at StackOverflow) the ISessionFactory interface is fundamental to how NHibernate works. As the StackOverflow links points out, creating a session factory is possibly the most expensive of the things NHibernate does during execution. A frequent misstep of developers new to NHibernate is to write code that will frequently – sometimes prior to each database call for the more heinous abusers – create session factory instances. As with any technology, that which isn’t used properly will probably result in less-than-favorable outcomes. NHQS simplifies this step for the developer, as well as facades the complexity associated with session factory storage once the application using the session factory has instantiated it.
If you’ve worked with me over the past year or you’ve seen one of my alt group meetings, chances are I’ve mentioned, demonstrated, or maybe stuffed down your throat, the NHQS thingamabob. With the improvements in NHibernate following .NET 4.0 and the experiences I learned in a few projects in the previous release I’ve decided to rewrite NHQS for NHibernate 3.xx. I like the improvements in NHibernate and with those and a slightly renewed focus on my goal for NHQS I felt it might be worthwhile to introduce it on its own into the wild. This post will introduce the world to NHQS and provide a guideline for its usage.