If it’s just for personal use, you can also just use SQLite. There’s a seeded driver + translator now available, so you can pretty easily point it to a local database. I think there’s a few issues (resolved in 8.0.15) with history, but if you just need simple relationship mapping it works great. Extremely portable, too - it’s a single file on disk you can plainly copy.
Also have to agree with Griffith here, I just needed some simple data storage, installed sqlite on my RPi 4, made a DB, and got it connected in less than 15 minutes. If helpful, I could make up a quick walkthrough.
One of my “little tricks” also has been to place that SQLite DB within the data/projects/ folder so that it gets incorporated into the gateway backup. Wouldn’t want to probably use this strategy for tag history or something that grows large over time, but it is a nice technique for bundling simple database assets that should be atomic with your Gateway.
FYI, In addition to MS SQL Express edition, MS now offered the the full version of SQL Server for free as a developer edition. The caveat is that the license is only for development and test systems, and not production.
But given that Maker edition is also only licensed for non-commercial use, then this shouldn’t be not an issue.
I use the developer version for developing (duh) work projects and haven’t had an issue with it.