It occured to me that the MySQL Connectors(Java and .NET) are GPL licensed.
Does that mean vendors(not developing for inhouse apps) will have to purcase a commercial license for proprietary software talking to a MySQL database through these connectors
GPL allows the commercial distribution of protected work.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same freedoms that you received. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
so you have to include a link to the mysql homepage or the source code somewhere in your programm (in the readme, maybe?)
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Conveying Non-Source Forms.
You may convey a covered work in object code form under the terms of sections 4 and 5, provided that you also convey the machine-readable Corresponding Source under the terms of this License, in one of these ways:
a) Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by the Corresponding Source fixed on a durable physical medium customarily used for software interchange.
b) Convey the object code in, or embodied in, a physical product (including a physical distribution medium), accompanied by a written offer, valid for at least three years and valid for as long as you offer spare parts or customer support for that product model, to give anyone who possesses the object code either (1) a copy of the Corresponding Source for all the software in the product that is covered by this License, on a durable physical medium customarily used for software interchange, for a price no more than your reasonable cost of physically performing this conveying of source, or (2) access to copy the Corresponding Source from a network server at no charge.
c) Convey individual copies of the object code with a copy of the written offer to provide the Corresponding Source. This alternative is allowed only occasionally and noncommercially, and only if you received the object code with such an offer, in accord with subsection 6b.
d) Convey the object code by offering access from a designated place (gratis or for a charge), and offer equivalent access to the Corresponding Source in the same way through the same place at no further charge. You need not require recipients to copy the Corresponding Source along with the object code. If the place to copy the object code is a network server, the Corresponding Source may be on a different server (operated by you or a third party) that supports equivalent copying facilities, provided you maintain clear directions next to the object code saying where to find the Corresponding Source. Regardless of what server hosts the Corresponding Source, you remain obligated to ensure that it is available for as long as needed to satisfy these requirements.
e) Convey the object code using peer-to-peer transmission, provided you inform other peers where the object code and Corresponding Source of the work are being offered to the general public at no charge under subsection 6d.
so a link, torrent, full copy of source are fine and it is not a derived work. hope that answers your question. At least that's what I get from reading the GPL. Though I'm no lawyer, so you might not want to take my word for it :)
oh and, taken from wikipedia:
Note that the copyleft applies only to the software and not to its output (unless that output is itself a derivative work of the program). For example, a public web portal running a modified derivative of a GPL'ed content management system is not required to distribute its changes to the underlying software because its output is not a derivative. A counter example is the GPL'ed GNU Bison: the parsers it outputs do contain parts of itself and are therefore derivatives which would fall under the GPL, if it were not for a special exception granted by GNU Bison.
wouldn't that mean that if you use the output of the connector in your program (which is basically what one does) that the license wouldn't apply in this case, other than distributing a copy of the connector and therefore providing a link to the homepage?
If you are linking to the MySQL connectors in your application then yes - your application is considered to be "work based on that Program" as per the GPL. You have 2 options:
License your application under a GPL compatible license.
Become a MySQL Ready Partner (free) and get one of your applications MySQL approved. This grants you access to the Connectors under a dual license - which will allow you to use the Connectors with proprietary code. More info here : https://partner-portal.mysql.com/guide/overview.html
(Note that the Connectors grants exceptions to the GPL licensing for open source projects.)
Does that mean vendors(not developing for inhouse apps) will have to purcase a commercial license for proprietary software talking to a MySQL database through these connectors
I'm not a lawyer but, to me, the key part is not developing for inhouse use which means distributing or selling as closed source. In that case, vendors need to purchase a commercial license, indeed.