dbMan is a complex SQL monitor for common database systems (PgSQL, Oracle, MySQL etc.). It's based on Perl and DBI interfaces. Features include a command history buffer, tab completion, editing Oracle objects, simultaneous connections, SQL help, importing and exporting of tables, Oracle explain plan, and more. dbMan is made as a simple kernel and many extension modules, and you can make your modules with a simple HOWTO.
DBPrism is an open source framework to generate dynamic XML from a database. It connects Oracle databases with Apache Cocoon, providing a high performance DBGenerator with functionality such as parallel content aggregation and ESI cache protocol. It also includes a powerlful database oriented CMS built on top of Apache Cocoon2 and DBPrism.
XMLDB uses an RDBMS to persist arbitrary XML documents. Due to its storage mechanism, searching for and recalling documents is extremely quick. You can also perform XSL translation on documents with surprising speed. The library can be used in any program to store libxml2 documents. A PHP module is also included, making XMLDB into a complete three-tier Web application development suite.
ora_mail is a tool for those of us who do not want to enable JServer for one reason or another. It is implemented as an external procedure that reads message data from CLOBS and passes it to and external program, such as qmail-inject or sendmail. There is also PL/SQL package that wraps arround this procedure to ease message creation.
Zephyr Basecamp is a functioning GTK frontend and PostgreSQL backend enterprise project that gives small and midsize businesses the same level of inventory, order entry, sales tracking, and accounting functionality as would be expected from commercial applications. It has interfaces for both X11/GNOME/Linux and Windows.