DataSet and DataReader are two fundamental objects in ADO.NET.
1. Dataset is a in-memory representation of database
2. DataSet is a disconnected orient architecture that means there is no need of active connections during work with datasets and it is a collection of DataTables and relations between tables
3. Dataset is readable and writable
4. Its possible to write and read XML data
1. Datareader is connected mode, and read and forward-only Data
2. DataReader will fetch the data very fast when compared with Dataset
3. Datareader is readonly