CAML queries against a database hosted on a RDBMS other than SQL Server?

We have a SharePoint 2007 site. It is supported by two back-end databases - one hosted on SQL Serv开发者_运维技巧er, another on an open-source RDBMS. We issue CAML queries to retrieve data from SQL Server, and ADO.NET queries to retrieve data from the other server. Our architect says we would be better off if we used the same approach (namely, CAML) to get data from the both databases.

Is it possible to use CAML queries to retrieve data from any RDBMS other than SQL Server? If so, please suggest any web resources, docs, anything you find appropriate.

CAML (at least that part used for SPList.GetItems queries) seems to be quite simple, so translating it into valid SQL statements should not be too complex. Which means, you could create a "translator module" and issue your queries against it. For instance, you can follow guidelines published in the article "[Implementing a .Net Framework Data Provider](http://msdn.microsoft.com/en-us/magazine/aa720164(VS.71).aspx)".