Bond
- A Linux rapid application development (RAD) tool for creating dynamic data aware database applications from standard design specifications.
- http://www.treshna.com/bond/

Index of Publicly Available Database Software
- Comprehensive list of research and other free database systems. Also includes some benchmarks. Maintained by ACM SIGMOD.
- http://www.sigmod.org/databaseSoftware/

Seva Software - ArunaDB
- Database server written in Ruby that supports tables, indexes, triggers, sequences, views, stored procedures, and transactions.
- http://sevainc.com/arunadb.html

MyOODB ( My Object-Oriented Database & Web Services )
- An Object-Oriented Database and Web Services (SDK) written in Java, includes documentation, example code and information about the author.
- http://www.myoodb.org

Axamol SQL Library
- Java library to execute SQL statements stored in external library files. This separation increases readability, eases maintenance, and allows separate testing and documentation. [MIT]
- http://www.slamb.org/projects/axamol/sql-library/

Arboretum Metric Access Method Library
- GBDI Arboretum is a portable C++ library which implements various Metric Access Method (MAM). By using this library applications will be able to perform similarity queries (queries by contents).
- http://gbdi.icmc.usp.br/arboretum/

Kexi
- 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.
- http://www.kexi-project.org/

MonetDB
- Open source high-performance database system developed at CWI, the Institute for Mathematics and Computer Science Research of The Netherlands.
- http://monetdb.cwi.nl/

CQL++
- Both a single user and client/server versions with ODBC drivers. Distributed under a modified GPL that allows distribution of applications without including source code. Commercial support available.
- http://www.cql.com/

SQLite
- C library that implements a self-contained, embeddable, zero-configuration SQL database engine. [Public Domain]
- http://www.sqlite.org/

ART
- A lightweight (Java/J2EE), multiplatform web based query tool and reporting environment. Supports tabular, crosstab, charts, scheduling; data exportable to spreadsheet.
- http://art.sourceforge.net

One$DB: Open Source Database
- Free and open source version of Java database Daffodil DB. Available in both network and embedded editions.
- http://www.daffodildb.com/one-dollar-db.html

ChurchInfo Church Database Application
- ChurchInfo is a php/mySQL database to keep track of people, families, groups, pledges and payments, sunday school classes, etc.
- http://www.churchdb.org

tdbengine - The turbo database engine
- tdbengine is a small but powerful RDBMS written in PASCAL. It runs on Linux as well as on Windows machines.
- http://www.tdbengine.org

ITTIA
- Provides small footprint, high performance, and easy-to-use embedded database solutions. Also sells technical support and consulting.
- http://www.ittia.com/

RekallRevealed
- 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]
- http://www.rekallrevealed.org

Qt SQL Browser
- A graphical front end for any ODBC compliant database [GPL]
- http://www.mobiustech.net/qtsql/

OSDB: The Open Source Database Network
- News, information, and tools related to open source database platforms.
- http://osdb.org

iSQL-VIewer
- An SQL browser tool that works with any JDBC 2.0 or higher driver. [Open Source, MPL]
- http://isql.sourceforge.net/

picoSQL
- picoSQL is a SQL-based, multi-user, client/server RDBMS, derived from a commercial project [GPL].
- http://www.picosoft.it/picosql/

Ocelot Computer Services Inc.
- 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]
- http://www.ocelot.ca

The TDB Replication System
- An open source suite of software that provides a high-performance, replicated, distributed peer-to-peer Unix DBM style database built on TDB.
- http://tdbrepl.inodes.org

Clip
- Object oriented, CA-Clipper and Xbase compatible compiler.
- http://www.english.itk.ru/clipper/index.html