What are some good books about databases?

Database System Concepts is the book we used in the first database class at Caltech. The first several chapters focus on describing relational algebra and developing a solid foundation for the next several to build on as they introduce SQL and discuss the kinds of tradeoffs you might make in schema design and query optimization.

It's a solid intro text in that if you approach it without any prior database knowledge and stick with it, by the end you'll not only know syntactically how to define a schema and write complex queries, you'll also have a good mental framework for normalizing your schemas, optimizing queries, and defining the right indices. That said, it is a bit denser than other intro texts, and it will take you a bit longer to get to actually working with a real database, as the first several chapters stick strictly to operations in relational algebra. This book is certainly not perfect, but it's far better than any other intro relational database text that I've come across.
Does one body part per day gain muscles?

Assuming that you are training a particular muscle group per day, (chest, back, arms, shoulders, legs, stomach), then the answer is a resounding yes, and no. Let me explain:As eluded to by Mike, splitting up your workouts into muscle groups allows you to shape your routine to concentrate the effort, and work

Will body weight workouts alone give me a toned body? Or should I do other workouts?

Of course body weight workouts can give you a toned body, but depending on your current fitness state and how heavy you are, it might not result in the type of toned body you are looking for. It also can take considerable time to get the results you might want and good knowledge