Pro C# 2010 and the .NET 4 Platform, Fifth Edition

21.9. Working with Data Readers

Once you establish the active connection and SQL command, the next step is to submit the query to the data source. As you might guess, you have a number of ways to do this. The DbDataReader type (which implements IDataReader) is the simplest and fastest way to obtain information from a data store. Recall that data readers represent a read-only, forward-only stream of data returned one record at a time. Given this, data readers are useful only when submitting SQL selection statements to the underlying data store.

Data readers are useful when you need to iterate over large amounts of data quickly and you do not need to maintain an in-memory representation. For example, if you request 20,000 records from a table ...