A DataSet can be typed or untyped. The difference is that
the typed DataSet has a schema and the untyped DataSet doesn't.
A typed DataSet gives easier access to the content of table fields through strongly typed programming. Strongly typed programming uses info from the underlying data schema. This means we are programming directly against your declared objects and not the tables. A typed DataSet has a reference to an XML schema file. This scema file(*.xsd) describes the structure of all the tables contained within the DataSet.
Try to refer this book Titled:"Database programming using vb
.net and SQL Server 2000".