Part V. MySQL and PHP Design Patterns

We must combine the toughness of the serpent with the softness of the dove, a tough mind and a tender heart.

—Martin Luther King, Jr.

All the interests of my reason, speculative as well as practical, combine in the three following questions: 1. What can I know? 2. What ought I to do? 3. What may I hope?

—Immanuel Kant

When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle.

—Edmund Burke

While some very advanced MySQL programmers use design patterns with relational databases, the four chapters in Part V use PHP design patterns employed in conjunction with MySQL. The MySQL example code in Part V uses simple MySQL statements. So you need not brush up on your JOIN statements or any other relational database code used with MySQL and PHP in the following four chapters.

However, the use of MySQL is so ubiquitous with PHP that not having a section on using OOP structures and design patterns with MySQL would be a serious oversight. Besides, this last section provides a way to add some more design patterns in PHP. They include the following:

  • Proxy

  • Strategy

  • Chain of Responsibility

  • Observer

None of these patterns are the exclusive domain of a combined PHP−MySQL application, and the patterns can be used perfectly well with PHP on its own. Further, in one of the Chain of Responsibility examples, you can see how more than one design pattern can be used together in a single application.

You will also find a combination interface and class that should take care of connections using mysqli. This little duo is employed throughout Part V, and once you substitute your own connection information—host, username, password, and database—you can use it for any MySQL connection you want.

While you will find no MySQL design patterns per se in Part V, you will find reusable structures that can be used with other PHP projects that employ MySQL. As experienced programmers know, making even small changes in PHP or MySQL code can wreak havoc on a program where both are present. However, you will find the well-structured design patterns handle changes with aplomb, even in a MySQL environment.