I played with Retina.net quite a bit when I first started looking at O/R Mappers to help generate a data access layer for my ASP.NET and Winform applications.
It showed a lot of promise, but eventually got placed on the back burner by the main developer as so many of our personal projects do as other opportunities and project work comes about. Andres moved the Retina.net O/R Mapper to CodePlex and is now finishing the .NET 2.0 Framework Version. He mentions it being released in about 3 weeks. As far as why you might want to use Retina.net over other O/R Mappers, Andres points out the following benefits and features:
"Just to name a few [interesting capabilities]: support to all kinds of relationships (composition, aggregation), support for all kinds of relationship multiplicity (1-1, 1-n, n-m), support for all three types of inheritance mapping, supports all major database engines, supports all kinds of primary keys (autogenerated in the db, compound, etc), supports a RQL (Retina Query Language) and Criteria objects for queries, supports lazy loading of child collections and entities (using dynamic proxies), paging and sorting in results, support for stored procedures, very easy to use with no complex XML config files, and many more.
Some unique, or first seen in, Retina.NET features:
- Supports the creation of entity "triggers" and "constraints".
- Extensible data type system.
- Support for data binding (including navegability of child entities and collections).
- Support for autogenerated edit forms (Web or WinForms).
- Very easy to implement a new database support."
Even though I know LINQ To SQL is out and the ADO.NET Entity Framework will soon be available, you may want to peek at Retina.net for your O/R Mapping needs.
Check it out on CodePlex.