Since I was in a situation where I had to finish the project quickly, I was going to skip this lecture and look at the Spring Boot roadmap, but I thought basic DB access technology was essential, so I took this lecture. In conclusion, I think it was a lecture that I was really glad to listen to. I think that the connection concept, connection pool transaction, lock concept, and Spring exception handling method are essential knowledge that can be skipped. One thing that was disappointing was that I haven't learned about transaction propagation yet, so if it had been included in this lecture, it would have been a better choice for the next learning direction. Thank you!!