ADO.NET provides classes that enable you to design and build a distributed data architecture. You can access databases in a connected or disconnected mode depending on your concurrency requirements. The DataSet enables you to work with data in a relational manner without being connected to any data source. XML can be used to model relational data inside an XML document that contains nonrelational information. A typed DataSet gives you the ability to work in a much easier, type-safe fashion with a DataSet , provided you have an XML Schema that defines your data.