Alternatives to MySQL that do not have a GPL licence

We have a built a new data fusion C++ algorithm which uses SQLite as an internal database.

However, we would like each of the multiple C++ threads to do a parallel db write and SQLite cannot do that.

So we are now looking at MySQL which allows each of t开发者_如何转开发he multiple C++ threads to do a parallel db write.

However, the MySQL non-GPL licence is too costly and we don't want to rely on Oracle for MySQL support since our data fusion C++ algorithm will soon have a US patent.

Are they are any alternatives to MySQL which allows each of the multiple C++ threads to do a parallel relational database write which do not have a costly licensing policy like ORACLE MySQL?

So far, I am starting to look at PostgreSQL's BSD license and Sybase open source relational database.

Could someone tell us if PostgreSQL or SYbase is the right direction to go in?

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PostgreSQL is definitely a very good alternative to MySQL.

In my opinion PostgreSQL is actually the better choice anyway looking at all the things that MySQL doesn't get right and the number of SQL features that they still don't have.

But again that's my personal opinion.

In terms of licensing the Postgres license is indeed more flexible for commercial usage than the GPL.

The support from the PostgreSQL community on the mailing list is outstanding - I don't know if there is something comparable in the Sybase world (actually I didn't know that Sybase is now OpenSource).

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There should be quite a few options. If you're not worried about being cross platform, you could try SQL Server Express. You can use this in production subject to some limitations (I think the limit relates to the type of hardware you can install it on). There is also an express edition of Oracle with similar usage constraints.

In the open source world, there is Firebird which I believe you should be able to use in embedded mode (that is, without having to install a separate network server process). I haven't used this in production but it has been around for many years and looking through SO, it seems to be well regarded. It uses MPL so there should be no licensing risks.

For completeness, you could consider MaxDB from SAP and the Ingres Database System. MaxDB seems to be a very capable DBMS but when I tried it years ago (version 7.6) it seemed to be extrodinarily difficult to work with. I've never worked with (or heard of anyone working with) Ingres but apparently it's open source and can be freely used.

Like "a_horse_with_no_name", I'm not aware of there being an open source edition of Sybase although I might have just missed it.

Phil