I suppose that you're talking about interfacing RhoConnect to a SQL Server database because, on the device, RhoElements uses SQLite.
I can suggest that you take a look at our documentation to have an understanding of the RhoConnect architecture.
There are even a couple of video available on the subject from last year North America App Forum:
From this content you'll discover that there're different ways to integrate the RhoConnect Integration Middleware with your SQL Server database, even a direct connection if this fit your solution. For a description of this scenario you can review the webinar:
Webinar 10/17/2012 - Direct Database Connectivity Using RhoConnect
Let me know if this answer your question or you need additional details.