Personally, I never believe in those "For Dummies" and "In 24 Hours".
Dummies don't do database design and programming and if it can be learnt in
24 hours, people don't pay much money for you to do the work. I don't even
believe the "In 21 days" books (OK, if you spend 12 hours a day for 21 days,
you learn a hell of a lot). At least in one "In 21 days" book, the author
implicitly admitted 21 days is not enough by providing 7 "bonus" chapters
not counted in 21 days. Of course these 7 bonus chapters cover tougher
topics.