Libgda 4.2.13 released with Firebird support (work is in progress)

Libgda is a (relatively small) database access library: it is a
wrapper like ODBC but with more features to access several database
engines * features a meta data extractor (to know all about database
objects in a common way) comes with an SQL console application

Work is in progress for Firebird (Check the git tree). There is also a
special feature which allows one to connect to a database hidden
behing a web server (through specific PHP scripts) * LGPL licensed for
the libraries and GPL licensed for the tools.

See http://www.gnome-db.org for more information.

ps: I like the Gda Browser Relation Diagram tool