Instruct: Classify Amazon reviews into positive or negative sentiment
Query: This book is very useful - I don't understand some comments

I really don't understand where some of the other comments on this book come from - I find it to contain lots of information I need, and I've been a DBA for 10 years. The source material of all Oracle books is ultimately the documentation, but these guys seem to have done a very good job of extracting what we need from the docs and presenting it in a useful form. The title is "Reference", so of course it will duplicate some Oracle material. To me, it looks like the init.ora chapter is pretty close to the docs, but they did cut out some unecessary words, and I'm not sure I could write those (boring) descriptions any better than Oracle already did, so why take a chance on introducing new errors? I think the book deserves 5 stars and the reviews that rate it low don't understand its purpose or have unrealistic expectations.