I bought the course because it covered the parts that I felt I needed, such as Oracle procedures and JSON communication, but I got so annoyed while listening to the lecture. When I actually turned on the lecture, it was obvious that the lecture was based on the assumption that I had learned it elsewhere, but if you're going to lecture like that, shouldn't you have informed me of the content that I need to study in advance??? I feel like I paid money for nothing. Also, the purpose of a lecture is to help students understand and understand it, but the pronunciation itself is so mumbled that it's really annoying, and since most of the code is copied and pasted, it's a lecture that makes me lose my desire to follow the lecture.