The book "Seven Databases in Seven Weeks" may be a good start. It may not answer all of your questions, but it does a good job summarizing various types of data

The book "Seven Databases in Seven Weeks" may be a good start. It may not answer all of your questions, but it does a good job summarizing various types of databases. Honestly you can read through it in a day or two - I don't think there's much need to install the DB's and do the exercises unless you're looking to explore a certain DB in more detail. I originally skipped over the first chapter on Postgres but went back and read it and learned a few things (too bad there's no mention of the recently added json and jsonb data types).