Hey Ryszard,
Great work! I've only checked it out globally, but it looks very nice. I'm always a big fan of keeping stuff separate, rather than integrating things into big blobs of code, so I'm glad you managed to make this a separate library. Have you found a way around the issues postgres has with creation and deletion of tables that have foreign keys referring to each other? (i.e. it will not let you put your database in an incorrect state)
Cheers, Marijn