DataAdapter is a part of the ADO.NET Data Provider. DataAdapter is used to retrieve data from a data source and populate tables within a DataSet. The DataAdapter also resolves changes made to the DataSet back to the data source. The Fill method uses the DataReader object implicitly to return the column names and types used to create the tables in the DataSet, as well as the data to populate the rows of the tables in the DataSet. Dataset represents a collection of data retrieved from the Data Source and saving data to the Data Source. We can use Dataset in combination with DataAdapter class.

The DataAdapter uses the Connection object of the .NET Framework data provider to connect to a data source and Command objects to retrieve data from and resolve changes to the data source. Each .NET Framework data provider included with the .NET Framework has a DataAdapter object. The .NET Framework Data Provider for OLEDB includes an OleDbDataAdapter object, the .NET Framework Data Provider for SQL Server includes a SqlDataAdapter object, and the .NET Framework Data Provider for ODBC includes an OdbcDataAdapter object.

Functionally DataAdapter is the complex Object when compare to other Objects in the Data Provider . From the following links you can learn more about DataAdapter in combination with dataset.