DataSets are IMDB, Almost
Anyone else remember the promised "In-Memory Database" (IMDB) that was to be part of COM+ some years back? Well, Microsoft has finally delivered a first version of it in ADO.NET's DataSet class.
For those who haven't take a look at ADO.NET yet, don't make the mistake of assuming the DataSet is a replacement of the Recordset from ADO. DataSets contain one or more tables. Tables can be setup with relationships, keys, constraints, etc. Though a real SQL engine does not exist (yet), DataSets do allow you to re-create some of your databases in memory. If you are attempting to scale your database servers, please take a look at this very cool technology!