Web Database Applications with PHP, and MySQL

Chapter 2. PHP

In this chapter, we introduce the PHP scripting language. PHP is similar to high-level languages such as C, Perl, Pascal, FORTRAN, and Java, and programmers who have experience with any of these languages should have little trouble learning PHP. This chapter serves as an introduction to PHP; it’s not a programming guide. We assume you are already familiar with programming in a high-level language.

The topics covered in this chapter include:

• PHP basics, including script structure, variables, supported types, constants, expressions, and type conversions

• Condition and branch statements supported by PHP, including if, if...else, and the switch statements

• Looping statements

• Arrays and array library functions

• Strings and string library functions

• Regular expressions

• Date and time functions

• Integer and float functions

• How to write functions, reuse components, and determine the scope and type of variables

• An introduction to PHP object-oriented programming support

• Common mistakes made by programmers new to PHP, and how to solve them

Programmers new to PHP should read Section 2.1, which describes the basic structure of a PHP script and its relationship to HTML, and includes discussion of how PHP handles variables and types. The two sections that follow, Section 2.2 and Section 2.3, deal with conditional statements and looping structures and should be familiar material. We then present a short example that puts many of the basic PHP concepts together.

The remainder of the chapter expands ...