NDO is a powerful object-relational mapping tool for .NET. NDO simplifies storing objects of your .NET classes in relational databases. Simply write business classes and mark them with the attribute [NDOPersistent]. Then recompile and NDO takes care for the persistency. NDO supports Linq queries to fetch your objects. NDO complies fully to the ECMA standard and the CLI, so your NDO-based applications run under mono as well as under Microsoft .NET and .NET Core.
See the sample here: