微软试图用所有这些数据访问策略解决什么问题？

There seems to be many different data access strategies coming out of Microsoft. There’s ‘classic’ ADO.NET, Linq2Sql, ADO.NET Entity Framework, ADO.NET Data Services, ADO.NET Dynamic Data. I’m sure that I’ve missed some. To me, it seems that there’s a lot of confusion surrounding where each frameworks fit into an application's architecture. What problem is Microsoft trying to solve with all of these data access methods?There seems to be many different data access st