Hello Young-han! I really enjoyed this lecture as well. At the beginning of the lecture, I thought "Oh, I just need to get a DB connection and send SQL to the database.." When I entered the transaction part, having only used SQL as scripts, I naturally thought I could just send transaction start queries one by one using PreparedStatement. However, when using transactions in a raw way, various problems started popping up one by one, and seeing how to handle them, why these errors occur, and how Spring has implemented solutions for them left me feeling both amazed and overwhelmed😆😆 I think this lecture, especially Spring's Transaction Problem Solving (Lecture 4), might be the 9th ridge of this course. Even watching it for the second time, it's not easy to understand. Just like when moving from MVC Part 1 to Part 2, it seems like Part 1 teaches concepts from the ground up first and then shows how to apply them, so I think I need to thoroughly review this DB Part 1 before moving on.. The developer's path is rough, and while Young-han probably doesn't even know who I am, I always consider Young-han as my life mentor and work hard with dedication! Thank you for always sharing many good words in your lectures. I wish you great success with the database roadmap as well!