<p>I have a large ADO.Net dataset and two database schemas (Oracle) with different constraints.  The dataset will work with either schema, but I want to be able to tell the dataset which schema to use (via connection string) at runtime.</p>

<p>Is that even possible?</p>

In the .Net 2.0 world, you can change your connection string on your table adapters at run-time.  You just have to be sure the Connnection property is public, which can be set from the dataset designer.