ADO relied on a connection based model. In the connected approach, the client had to be connected with the server and remain connected till the whole procedure or transaction was completed. Time resources and bandwidth became major constraints on such architecture.
To solve this problem the latter version of ADO used RecordSet. All the contents from the data source were copied into RecordSet. This allows clients to get disconnected from the server, work on the RecordSet and copy the changes back to the data source again. This approach did not succeed much because it requires COM marshalling to transmit disconnected data, it support only those datatypes that were defined by the COM standards and hence required type conversion.
ADO.NET can be used to access data sources using new .NET data providers as well as existing OLEDB data providers using the OLEDB.NET data provider.