This book includes the latest version of PHP - version 5 - and focuses on the capabilities within the framework of multi-tier applications. A chapter discusses object orientation in PHP that apply to multi-tier architecture and other chapters discuss the HTTP and SOAP, two communication protocols are most useful in tying together multiple layers. Includes PHP-related aspects of software development in multi-tier environment, which is important to develop powerful software with low cost and ease of use as design objectives. InnoDB supports true referential integrity and row-level locking. Examples of applications (multi-currency bookkeeping application money) runs throughout the book, showing various PHP capabilities as well as database interactions.