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From:Zak Greant Date:August 7 2004 5:17am
Subject:Re: using mysql in commercial software
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Hi Mike,

On Aug 06, 2004, at 18:08, mos wrote:
>> This means
>> that, according to the most common interpretation of the GPL, just
>> linking with them automatically requires your code be under the GPL.
> License: >>The GPL license is contagious in the sense that when a 
> program is linked to a GPL program, all the source code for all the 
> parts of the resulting product must also be released under the GPL. <<

One important note here: The GPL does not behave in the way described 
above. There is no requirement to distribute software that you build 
with or on top of GPL-licensed software to others.

However, if you choose to distribute software that is a derivative work 
(defined in US copyright law as " A ''derivative work'' is a work based 
upon one or more preexisting works") of GPL-licensed software, then the 
software can only be distributed under the GPL.

> So what if the client app doesn't require the MySql client libraries 
> in order to access the MySQL database? My client application requires 
> no dll's at all, because everything is compiled inside an .exe file. 
> That's because I'm using a 3rd party set of components that bypasses 
> the libmysql*.dll libraries altogether. My application doesn't link to 
> MySQL's code, GPL or otherwise. Does this now make my application 
> license free even if I distribute it for $$$? Or will the software 
> police come banging on my door at 4 AM looking for me?

This architecture might bypass the requirements of the GPL - I don't 
really know. The best course of action here is to consult a lawyer who 
is an expert in Free Software/Open Source software licensing who can 
advise you of the validity of your course of action for your given 

We would probably assert that the software forms a derivative work with 
GPL-licensed MySQL because the software would likely not function 
without MySQL. However, this is a tough area to speculate on.

As we are not lawyers (nor are we in the business of giving free legal 
advice to help people circumvent our own business model :), we always 
recommend that proprietary applications (aka applications that do not 
share their source code and the rights to modify it with others) should 
always use the proprietarily licensed version of MySQL.  This 
recommendation ensures that our licensing terms are never violated and 
helps us generate revenue to fund development of the database. Usually, 
people who distribute proprietary applications are selling them. We 
feel that it is reasonable to charge users who wish to charge their 
users and who do not give their users the freedom to view, modify and 
share the source of the application.

We also suggest that people consider putting their software under a 
Free Software/Open Source license (such as the GPL, the BSD license, 
the Apache license and so on). Then they can use MySQL for free. This 
model may not work for everyone, but there is still significant 
potential for revenue with the model by selling the application at a 
fee that the market finds reasonable, along with related services like 
hosting, support, consulting, etc.

People may also want to consider using a dual-licensing model that 
allows them to share with others who choose to use Open Source/Free 
Software licenses, but gives them a revenue stream from people who 
prefer traditional proprietary licenses.

Zak Greant
MySQL AB Community Advocate

Re: using mysql in commercial softwaremos7 Aug
  • Re: using mysql in commercial softwareZak Greant7 Aug
Re: using mysql in commercial softwareZak Greant10 Aug