DataReader

A DataReader is a read-only forward-only way of reading data. It is quiet fast when compared to fetching data using a DataSet.
Some important point:
Read-only access
Supports a single table based on a single SQL query of one database
Connected mode
Bind to a single control
Forward-only scanning of data
Faster access to data
Lightweight object with very little overhead
Must be manually coded

Code Sample:
SqlConnection myconn = new SqlConnection(connString);
SqlCommand mycomm = new SqlCommand("select * from emp", myconn);
mycomm.Connection.Open();
SqlDataReader dr =
mycomm.ExecuteReader(CommandBehavior.CloseConnection);
while(dr.Read())
{
Console.WriteLined(r.GetString(0));
}
dr.Close();
myconn.Close();

Thanks & Regards
Santosh