HSQLDB - 100% Java Database
Version 2.5.0 was released in June 2019. Version 2.5.1 is
currently in release candidate stage.
2005-today: After the release of version 1.8.0 in 2005, we aimed to develop a highly standard-compliant database engine to support advanced data types and Standard SQL syntax. This required a complete rewrite of most core and interface components of the engine and was done in stages over four years. We avoided early releases in order to provide a well-balanced feature set.
Version 2.0.0 was finally released in June 2010, after several alpha, beta and RC releases and extensive public tests over a year. We completed all the features listed in the new features page.
Since the release of 2.0.0, we have added enhancements, new features and fixed reported bugs, resulting in version 2.5.0 in June 2019. Point releases have appeared on average twice a year. Recent new features include hot backup, multi-billion row tables, extended SQL syntax compatibility modes, JEE XA transactions, connection pool and many new built-in functions.
In addition to regular enhancements to all areas of the engine, we will be enhancing and completing the additional features listed below, which are in an advanced stage of development (or nearly complete). (See the SupportWare page on how you can support the effort financially):
Developers are currently needed to write tests and improve the .NET and ODBC support for public release.
The development effort and all public releases are coordinated by the full-time Maintainer to ensure continuity and consistency.
We are always looking for new developers to join our team.
Anyone who would like to contribute code, tests, documentation
or translation is welcome to join. Please send an email to the
Maintainer, Fred Toussi, fredt (at) users.sourceforge.net
with your proposed enhancement. When you contribute code, you
are expected to contribute tests that validate your code.
HSQLDB is used in (or is supported by) a large number of open source projects. We welcome direct, priority contact with developers from those projects to ensure a smooth transition to new versions. You can point us to the HSQLDB access code in your pre-release sources and we will look and suggest any simple improvements that may be necessary.
We value contributions from all developers who use HSQLDB in
their projects. We have been able to fulfil many requests for
additional features or bug fixes and will continue to give
priority to what users ask for.
You can discuss patch contribution directly with the
Maintainer. You are encouraged to report any issues during
development and we will fix them promptly. You are also invited
to join SupportWare to
contribute to on-going development and maintenance of HSQLDB.
Development of HSQLDB 2.x and other components is reflected in the SVN repository. The directories are listed below:
/base version 2.x
/base-one versions up to 1.8.x
/dotnet the .NET implementation of 1.8.x
/odbc the ODBC driver
The changelist for
version 2.x shows all the changes since version 2.0.
Before HSQLDB: Hypersonic SQL was a small open-source all-Java database engine, first released with source in 1998. By the year 2000 and version 1.43 it had developed into a simple and basic SQL engine. The Hypersonic SQL project stopped development in late 2000 and was closed in 2001.
2001: In March 2001, a number of developers who were using the software for their work got together through the Internet and formed the HSQLDB Development Group to continue the development. The Group released the first version of HSQLDB (1.60) in April 2001, featuring support for SQL triggers and other enhancements and bug fixes. The next version (1.61) followed in July that year.
2002: Growing interest in HSQLDB resulted in more and more enhancements and new features submitted to the project. Development continued for the next 12 months and the next version, 1.7.0, was released with major new functionality, especially Text tables. Version 1.7.1 followed in October with further enhancements. Many old bugs inherited from Hypersonic SQL were fixed in these versions.
2003-2004: Work on version 1.7.2 continued until July 2004 when 1.7.2 was finally released after extensive testing. Features such as compiled prepared statements, cascading deletes and updates where introduced. We continued to fix reported bugs against 1.7.2 and released 10 revisions of the engine. Thomas Mueller, the author of Hypersonic SQL, made a welcome reappearance in 2004 for a short period and submitted enhancements to NULL handling. We released version 1.7.3 in 2004.
2004-2005: Simultaneous development on the next version, now designated as 1.8.0, was carried out in the second half of 2004. We introduced changes made by Ocke Janssen for OpenOffice.org integration. We also rewrote the whole area of code that controls persistence and handles memory caching of disk based rows. This made HSQLDB yet more resilient and capable of handling huge tables. Several important new features were also developed, including database schemata, roles and new SQL features. The first release of 1.8.0 came out in July 2005. In the process leading to 1.8.0 the code was modularized, all internal functionality was reviewed or rewritten and regression test coverage of various features were greatly improved. Version 1.8 had regular bug fixes and improvements from its release until the last version 1.8.10 was released in 2010.