有一个在我的答案在这里：的 MVC3和实体框架

Have a look at my answer here: mvc3 and entity Framework

其实分层和分离关注这个逻辑也适用于MVC，的WinForms，WPF，SL等等...在这样的层次堆栈只有DAL（数据访问层）的影响，并需要更新，一切保持不变。

in fact this logic of layering and separation of concerns applies to MVC, WinForms, WPF, SL and so on... in such layered stack only the DAL (Data Access Layer) is impacted and needs to be updated, everything else stays the same.

我的建议是让别的不说这样的DAL类库分离，并在那里，正如你所说，你应该替换的SqlConnection 和的SqlCommand 与Oracle的。

my suggestion is to make such DAL class library separated from anything else and in there, as you mentioned, you should replace SqlConnection and SqlCommand with the Oracle ones.