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 (like mysql, psql or sqlite3 consoles)
* relies on GLib, coded in C, its API is easy to use
* at the moment supports SQLite (and SQLCipher), MySQL, PostgreSQL, MSAccess, Berkeley Db (and is SQL extension), Oracle and JDBC (allows access to any database through a JDBC driver), work is in progress for other database types (such as Firebird). 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.