Is there a way to integrate an OPF (Object Persistent Framework) or ORM
(Object Relational Mapper) with Firebird?

I have written an OPF that uses a DAL (Data Access Layer) to support
numerous databases. I was contemplating whether I should or could
reduce the expense of the OPF by integrating it with the Firebird
engine somehow, or reducing the DAL overhead by making direct API calls.

Anyone done something like this? Is it possible?