The developers at Mindscape have a fantastic Visual Designer for their LightSpeed O/R Mapper that integrates into Visual Studio. I absolutely love the roundtrip synchronization between the database and domain model as well as the added support for refactoring, inheritance, migrations, etc. The number of features and ease-of-use shows Mindscape's deep commitment to making the developer experience as productive and pleasurable as possible.
The other day they released a separate product, called NHibernate Designer, that offers similar functionality for those developers using the NHibernate O/R Mapper. Again, this is a Visual Designer that quickly and easily integrates within Visual Studio and allows you to do model-first development using the designer or reverse engineer tables from a database. As you make changes to the model or the database you can easily synchronize them to your heart's delight:
Under the covers the NHibernate Visual Designer is creating and managing the necessary domain entities as well as the XML Mapping that NHibernate needs in order to properly map your classes to the database. This saves you an incredible amount of time and headache and allows you to focus on the domain and its rich behavior as opposed to the friction associated with the O/R Mapping Infrastructure. The NHibernate Designer also contains a simple ConfigurationHelper that takes care of extracting the mapping information created by the designer and integrating that with the other NHibernate configuration details in your app.config, web.config, etc.
I haven't spent a lot of time with the designer, but I am very excited about the possibilities. I created a simple Blog Model with Post and Category Entities using the designer and a Comment Entity reverse engineered from the database and the synchronization worked beautifully. The Mapping Configuration worked flawlessly as well using their ConfigurationHelper because within about 10-15 minutes I was successfully using NHibernate and LINQ To NHibernate to handle all my data access needs for this simple model.
Mindscape is really good at adding new features and fixing bugs as part of their nightly builds, so if you are interested in a visual design surface for NHibernate that integrates within Visual Studio, I recommend you download the free trial, pound on it, and give them feedback as to any bugs and missing functionality in the product. Download the trial here.
David Hayden