数据访问层 - 从本地SQL数据库切换到云数据存储

I am creating a simple application and getting stuck with data storage option. To begin with I would like to use SQL Server as my data storage. I will not be using any special features of SQL Server, its pure tables with CRUD operations. Now I should be able to switch the underlying data store to either SQL Data Services or Amazon S3 by changing few configuration parameters.I am creating a simple application and getting