(The book consists of eight chapters, each with a theme; Chapter 1 reiterates the core concepts and technologies of object-oriented programming to ensure that developers who lack basic knowledge can correctly understand them; Chapter 2 summarizes the basic concepts and technologies of PHP development and various database related best practices, such as data persistence, data storage, MySQL use, PDO, database design, etc; Chapter 3 explains the API and how to use it in detail; Chapter 4 summarizes the commonly used PHP development design patterns and their application principles; Chapter 5 explains how to write safe PHP code, summarizes and analyzes various common security problems in PHP development; Chapter 6 focuses on benchmark, system test and database, and discusses the performance of PHP applications from the aspects of file system; Chapter 7 explains the automatic testing of PHP, including unit testing, database testing, load balancing testing, etc; Chapter 8 summarizes the best practices related to quality assurance in PHP development practice, including quality measurement, coding standards, source code management, automatic deployment, etc. In addition, the book also explains pear, PECL and PHP standard libraries.)