Glom uses PostgreSQL and doesn’t try to offer the user a choice of anything else. That’s because it does what Glom needs, there’s no need to confound the user with an incomprehensible choice, and I’ve no wish to maintain multiple sets of code. It’s hard enough keeping up with changes in PostgreSQL, though Glom’s regression tests help.
However, I played around with adding MySQL support as a build-time alternative via the –enable-mysql configure option. The basic stuff now works both in the UI and in the regression tests. Those tests can now run each self-hosting database test with all 3 backends.
This is mostly just so I could learn about MySQL, so I can reimplement it in Java for OnlineGlom. That would let me use Google’s Cloud SQL, which is based on MySQL. The main work has been figuring out how to initialize a MySQL database store on disk and then start and stop MySQL instances. It’s even more funky than with PostgreSQL. I did need an addition to libgda to support non-standard MySQL port numbers but, as usual, Vivien Malerba fixed that for me quickly. There’s also the rather huge problem that AppArmor on Ubuntu prevents us from starting MySQL with anything but the standard database data, and we can’t expect the user to go editing AppArmor config files. At least with MySQL 5.6, it should be possible to start a MySQL instance without it having no password for a few seconds, as is necessary with MySQL 5.5. I need to start and stop custom instances so I can run tests automatically.
I’ve committed it to Glom’s git master, and its in the 1.23.3 release, just in case anyone wants to improve it. There are some TODO_MySQL comments in the tests where we expect something to fail with MySQL. For instance, I have not added support for editing the MySQL users and groups. And there are likely to be problems with keeping data when changing field types, which doesn’t seem to be tested thoroughly for any backend. libgda is also missing some support for binary field types, needed for Glom’s image fields.
Over the years, various people have complained about Glom not using MySQL. Here is your chance to actually work on that, with tests to show if your work is enough.