To answer your question – yes, people do often switch to another provider at runtime.  At design-time we need an OLE-DB compliant provider to ensure that the scheme can be read successfully, but at run time most people are concerned with performance so if there’s a faster driver that works they will use it instead.  DevForce currently supports the SQL Server and Oracle .NET providers, and might need a little tweaking to recognize a new .NET provider, so I can’t promise that the Informix driver would work out of the box. Inverting your question, the reason people might stick with the OLE-DB provider at runtime is that it supports a broader array of databases.