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Open Source Licence

The RAQUEL DBMS is being produced under the GNU Lesser General Public Licence (LGPL) version 3. See GNU Lesser General Public License for details.

Likewise any related software – e.g. the GUI Frontend - that the Raquel Database System project produces will also be produced under this licence.

It is desirable to maximise the opportunities and support for the Open Source development of the RAQUEL DBMS and related software. It is also planned to use pre-existing open source software as components of the DBMS and related software wherever possible.

Thus initially it was decided to use the GNU General Public Licence (GPL) version 3, as this is most supportive of this strategy. However a DBMS, by its very nature, always has some kind of ‘driver application’ that submits statements for execution (in this case written in RAQUEL) and receives the results of executing the results of the statements. These applications can vary widely and may well include proprietary software as well as other open source software. Also it is the long-term goal of the Raquel Database System project to make the architecture of the DBMS much more flexible than that of the traditional monolithic DBMS products, so that it could be used with driver applications in a much greater variety of ways. According to page 101 of Karl Fogel’s book Producing Open Source Software, this would be precluded by the GNU GPL Licence, because that licence is “deliberately crafted .. to make it impossible to mix GPLed code into proprietary programs”. See GNU General Public Licences for details.

Hence the GNU LGPL version 3 is used to obtain the strongest open source licencing possible without losing the freedom to use the software in useful combinations that would otherwise be precluded by GPL version 3.

The MIT / X Window System Licence was also considered, for the same reason, but is not as well known as GNU’s licences (and may lack open source protection), and so was not chosen.

Note : see also GNU compatible and incompatible licences.