Can you give a overview of ADO.NET architecture ?

The most important section in ADO.NET architecture is gData Providerh. Data Provider provides access to datasource (SQL SERVER, ACCESS, ORACLE).In short it provides object to achieve functionalities like opening and closing connection, retrieve data and update data. In the below figure you can see the four main sections of a data provider
ã Connection.
ã Command object (This is the responsible object to use stored procedures)
ã Data Adapter (This object acts as a bridge between datastore and dataset).
ã Datareader (This object reads data from data store in forward only mode). Dataset object represents disconnected and cached data. If you see the diagram it is not in direct connection with the data store (SQL SERVER, ORACLE etc) rather it talks with Data adapter, who is responsible for filling the dataset. Dataset can have one or more Datatable and relations.

“DataView” object is used to sort and filter data in Datatable.
Note:- This is one of the favorite questions in .NET. Just paste the picture in your mind and during interview try to refer that image.