Database abstration layers

Dear all,

I am looking at available database abstraction layers with the idea of 
porting pgAdmin2 to Linux. This is just for information, my project is not 
clear by now.

GnomeDB (http://www.gnome-db.org) seems quite fantastic when used in 
conjunction with Glade. Until now, I never heard of any abstraction layer 
under KDE. Is there any?

By the way, I looked at KDE TOra, which seems very Oracle centric. TOra seems 
to be built upon database wrappers, not abstraction layer classes. Am I wrong?

What is the best database abstraction under Linux ? Any idea, suggestion, 
etc.. are welcome. 

Best regards,
Jean-Michel POURE