Question

I dont know about open source, I read some licenses but I want to know about your experiences about it, my goal is write my software and make a redistributable with postgreSQL, can I do it without pay any fee? I read something about MySQL, that you need pay a fee if you make a redistributable of this in your software release.

Answer 1

I am not a lawyer, and this does not constitute legal advice.

PostgreSQL, including the Npgsql driver you are using, is licensed under the terms of the PostgreSQL license. The primary clause of the license is:

Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.

Bundling PostgreSQL and the driver with your software is fine. The license is very similar to the MIT license, which boils down to “do whatever you want, just include a copy of the license text and don’t misrepresent ownership or omit the copyright notices.”

This is one of the primary reasons I prefer PostgreSQL over MySQL for new development; the official MySQL client libraries are licensed under the GPL, which means you need to purchase a commercial license to distribute proprietary code that uses those libraries.