APQ is an Ada95 thick binding to allow Ada SQL client programs to access PostgreSQL, MySQL and Sybase database systems. The project is now hosted at http://framework.kow.com.br
Vela is a Open Source SQL and PL/SQL client software for Oracle database with a graphical user interface developed using Java Swing. It is a Front-End tool for a Oracle developer. It supports most of the common developer tasks.
DB Copy Plugin is a plugin for the SQuirreL SQL Client (1.2beta6 and 2.0 RC1+) that allows copying database objects (schema def and data) from one session window to another. The sessions can be disparate database vendors (Oracle -> MySQL, for instance).
Lightweight SQL querying tool written in Java. Connects to any JDBC compliant database and will run on any OS with a Java VM. Features: keyword highlighting, result formatting, statement history, multi-window, multiple database connects at one time.
SQL Star, a SQL client provides a common Graphical User Interface (GUI) for all database servers (like, oracle, microsoft sql server, mysql etc.,) using JAVA JDBC 3.0 API With type 4 driver.
lib4d_sql is a C library providing the required functions (connect, prepare, execute, ...) to write a SQL client for 4D databases. It uses the public 4D SQL protocol wich is supported by 4D products since... the version 11. It is already used by the PDO_