Why should we separate DataSet code from DataAccess code?

Question

I've been converting my WinForm application using a tiered approach following this article: http://msdn.microsoft.com/en-us/library/vstudio/bb384570.aspx

In the article, it recommends creating two separate class libraries, one for the typed DataSet class and one for DataAccess. I figured these two entities are fairly coupled logically, so why divide them?

Answer 1

You want to be able to reference your strongly typed data model without referencing any of the lower-level data access APIs. Your consuming code shouldn't have any awareness of where your data model originates from. You might want to use your data model in your UI layer. Your UI layer just needs to know about the model, not how the model is populated with data.