This is a companion volume to ''The Database Book: Principles and Practice Using MySQL. Here, the open source MySQL database system is used to illustrate the writing of database applications. The book is ideal for a first course on database applications or as a second book for a course on databases. It is also a perfect companion for software professionals in the business of writing database applications. The book begins with a review of relational databases and SQL to lay the basis for application development. The requirements of a web-based database application (an online book store is taken as an illustrative example), the possible database application architectures for the same and the writing of applications using JSP and PHP with MySQL database API are covered in the book. An implementable prototype that is robust and of production quality is developed in the process.