Different things work better for different people, or sometimes not at all! I learned about databases from the age of 14 in school and continued formal learning until 19, combined with online resources (by far my greatest source) and the occasional book. I'm still learning new things even now, 10 years later. Perhaps this long-term approach is somewhat lacking in today's world.

As for any ebooks on the subject, I have none at hand (I rarely use ebooks at all, so never go to look for them) but I would be very surprised if there aren't good ones available easily. Hopefully some other member(s) will have used that particular resource type in the past.