Open source high-performance database system developed at CWI, the Institute for Mathematics and Computer Science Research of The Netherlands.

An SQL browser tool that works with any JDBC 2.0 or higher driver. [Open Source, MPL]

An integrated environment for managing data. It helps creating database schemas, inserting, querying and processing data. Screenshots, downloads, resources, a wiki and a list of involved developers.

tdbengine is a small but powerful RDBMS written in PASCAL. It runs on Linux as well as on Windows machines.

The Ocelot SQL DBMS adheres closely to the ANSI/ISO SQL standard. The site has software downloads, tutorial information, and reviews of SQL or general DBMS books. [Mozilla and GPL]

A Linux rapid application development (RAD) tool for creating dynamic data aware database applications from standard design specifications.

A graphical front end for any ODBC compliant database [GPL]

A list of research and other free database systems. Also includes some benchmarks. Maintained by ACM SIGMOD.

Rekall is an open source database front end, in the style of Microsoft Access. It is built on Qt and KDE and runs on Linux and Windows. Open source drivers available for MySQL, PgSQL and XBase (DB4 via a wrapper library) [GPL]

A lightweight (Java/J2EE), multiplatform web based query tool and reporting environment. Supports tabular, crosstab, charts, scheduling; data exportable to spreadsheet.