Accessing MS SQL Server 7 and InterBase 6 without BDE

I'm writing an application that will need to access the same database schema
which may be placed on a variety of vendor databases; initially, InterBase
and MS SQL Server.  I don't want to develop multiple versions of the
application to support the various databases.  However, I  would like to
avoid using the BDE as well.  Any suggestion on how best to proceed?

Eric Wilson