Libgda is a (relatively small) database access library. It provides a wrapper like ODBC but with more features for accessing several database engines, a general data model for use with CSV or XML files, a metadata extractor that retrieves information about database objects in a common way, and a SQL console application (like mysql, psql or sqlite3 consoles).
Déjà Dup is a simple backup tool. It hides the complexity of doing backups the 'right way' (encrypted, off-site, and regularly) and uses duplicity as the backend. It features upport for local or remote backup locations, including Amazon S3. It securely encrypts and compresses your data. It incrementally backs up, letting you restore from any particular backup. It schedules regular backups, and integrates well into your GNOME desktop.