DataSets vs. DataReaders

I am stepping into heretical territory here, so you will have to pardon my trepidation.  I am going to discuss something over which wars have been fought, reputations destroyed and live ruined.  Yes, you guessed it, I am going to discuss DataSets vs. DataReaders.

There has been much discussion of this topic behind closed doors and even the occasional directive stating that if you are passing large amounts of data from one tier to another, use a DataSet.  DataSets are indeed convenient mechanisms for transporting around a lot of information that can be stored in a table/row manner.  What happens, though, if you are retrieving a single value?  What if you are going to be retrieving data until a specific event occurs (time or data initiated) and then stop processing?  My contention is that these items may be better suited to a DataReader as opposed to a DataSet.

A DataSet is much lighter weight and is actually the underpinnings upon which the DataSet is built.  When you issue the Fill command to a DataSet it uses a DataReader to retrieve all of the data which it then passes back to you.  if you don't need all of the data, however, you just chewed up a lot of processing cycles, processing memory, and your clients time, retrieving data that you are going to throw away.  If you are in a memory constrained situation or a time constrained situation it may be more appropriate to use a DataReader instead as that will give you more control.  Is it difficult to use?  Heck, no.

So, what is that I am advocating?  Education.  Learn the differences between a DataSet and a DataReader and when each is the most appropriate alternative.  Understand the weaknesses of each, not just the strengths.  Then, only then, make an intelligent, informed decision about the right tool to use.