Silverlight和WPF独立应用程序版本的数据访问技术

I am writing an applicaton that will be a standalone WPF application and also a cut down version that will work as Silverlight and so be hosted in browsers. I want the Silverlight application to access data from the cloud. The WPF application needs to work against a local database but then be able to sync with the same cloud storage.I am writing an applicaton that will be a stand