Silberschatz, Korth, Sudarshan: Database System Concepts (5th ed). Mc Graw Hill, 2005.
Copies of the 5th edition have been ordered and are available at the University Bookstore. Of course, you can get the textbook also from somewhere else.
Don't buy heavy and often useless SQL books, many of them are just copies from Oracle's Online Documentation!!! If you want to buy a book about PL/SQL or Oracle-specific issues, stop by my office and I can recommend some good books (see also below).
Handouts, which summarize sections of the book, can be obtained from this site. Note that the handouts don't include examples that I present in class. So just having the handouts isn't sufficient for succeeding in this class!