GPL and commercial licensing, MySQL dual licensing policy

John Cowan jcowan at
Mon Feb 4 18:28:15 UTC 2002

Mikko Valimaki wrote:

> I don't get it: why would MySQL require a commercial license if you only
> *ship* your (commercial) product "that requires MySQL" with MySQL
> server?

Because the MySQL AB people think that if your product requires MySQL
(= works only with MySQL), then aggregating MySQL with it is the same
as linking MySQL to it: you have in effect created a derivative work.
This is legally dubious.  The _C Answer Book_ by Tondo and Gimpel
gives answers to the questions in K&R, and so only "works with" K&R
(and only with a specific edition at that); but that does not make it a
derivative work of K&R.

If your product works with more than one database, then is no
possible claim of a derivative work.

> GPL fag practically gives up in explaining what this means: "What
> constitutes combining two parts into one program? This is a legal
> question, which ultimately judges will decide."

Unfortunately this is simply the case.  The GPL (or any copyright
license) cannot control the creation of programs which are not
derivative works of the original GPLed program, and "derivative work"
is a legal term whose meaning depends essentially on court decisions,
which hardly exist in the software realm.

> Consider this example: is a graphical MySQL client "based on MySQL"?
> Someone could say yes.

In general nobody supposes that clients and servers are parts of
the same work.  The whole point of having them is so that they
can operate independently of each other.

John Cowan <jcowan at>
I amar prestar aen, han mathon ne nen,
han mathon ne chae, a han noston ne 'wilith.  --Galadriel, _LOTR:FOTR_

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