Yes, it seems the tiOPF website is a bit out of date. There appears to be support for both MySQL and PostgreSQL.
I tried to get started by reading
http://tiopf.sourceforge.net/Doc/PersistingObjectsAndRelationships/SimpleCollection/, yet I keep running into troubles. Firstly, it's focussed on Delphi, so I cannot apply it 1:1 to Lazarus.
Secondly, at one point, the author suddenly uses a TPerson.Save method that was never properly introduced. I simply exported it (like the earlier TPersonList.Read) but nothing happens to my DB when I call it (even when I switch to CSV database for testing purposes).
Thirdly, I installed the tiOPF packages like described here:
http://wiki.lazarus.freepascal.org/tiOPF. But when I try to drop any TtiPerAwareXXXX component on the form, all I get are two access violation messages (one for creation and one for destruction of the component).
Fourthly, the mailing list link at the project's website leads to a dead end:
https://lists.sourceforge.net/lists/listinfo/tiopf-talk.
Is this software really mature and under active development? Or is just me being incredibly stupid?
I think I'll try to take a look at Greyhound before trying to untangle that ball of yarn. Given the ease of the dataset approach, I was hoping for a similarly easy O/R solution. You know, write a BOM, drop a component that links the BOM to the DB and maybe another one that links BOM and GUI and be done with it. Seems it's not that easy at all.