PHP与MySQL：全面指南第二版

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"《PHP&MySQL：The Missing Manual》第二版是由Brett McLaughlin编写的权威指南，这本书在IT行业中广受欢迎。作为PHP和MySQL技术领域的经典之作，它填补了初学者和专业人士在快速理解和掌握这两种核心技术时常常缺失的重要教程。该书不仅深入浅出地介绍了PHP语言的基础知识，如变量、数据类型、控制结构等，还着重讲解了如何与MySQL数据库进行高效交互，包括SQL查询、连接操作、表设计等内容。在第二版中，作者对原有的内容进行了更新和扩充，以适应PHP和MySQL技术的最新发展。2012年11月首次发布的修订版，旨在解决初学者在学习过程中可能遇到的问题，并提供了最新的最佳实践和解决方案。此外，O'Reilly Media作为出版社，注重版权保护，并鼓励教育、商业或销售推广用途的购买。本书的独特之处在于其实用性和易读性，强调将复杂的技术概念简化，使读者能够迅速上手并建立坚实的基础。书中包含了大量的实例和练习，帮助读者通过实践巩固所学知识。对于那些初次接触PHP和MySQL，或者希望提升现有技能的专业人士来说，《PHP&MySQL：The Missing Manual》无疑是一本不可或缺的参考书籍。如果你正在寻找一本既全面又易于理解的PHP和MySQL教程，这本书无疑是你的理想选择。无论是自学还是教学，它都能提供一个系统的学习路径，让你在处理实际项目时更加得心应手。通过阅读和实践书中的内容，你将能够有效地利用这两种技术构建动态网站，提升开发效率，进一步推动职业生涯的发展。"

PHP & MYSQL: THE MISSING MANUAL

WHAT IS PHP?

// Run the query

$result = mysql_query($select_query);

// Assign values to variables

<html>

<head>

</head>

<body>

<div id="header"><h1>PHP & MySQL: The Missing Manual</h1></div>

<div id="example">User Profile</div>

<p><img src="show_image.php?image_id=<?php echo $image_id; ?>"

class="user_pic" />

<?php echo $bio; ?></p>

<p class="contact_info">Get in touch with <?php echo $first_name; ?>:</

<ul>

</html>

This script references another script,

database_connection.php,

and then extracts

a user’s ID from the request parameters sent by a web browser. The script uses that

ID to search a database for the rest of the user’s information. Then, it builds the data

into a web page that’s created on the ﬂy.

The result? Pages that are both full of HTML and have dynamic content, like Figure I-2.

FIGURE I-2

This page is as much PHP as HTML. It looks up your visitor’s

name in the database and displays it dynamically. The menu

creates a Show Profile option specific to this user. But there’s

still lots and lots of HTML. This is PHP at its best: combining

the HTML (and even JavaScript) that you know with the PHP

you’re about to learn.

INTRODUCTION

WHAT IS PHP?

JavaScript Is Loose, PHP Is…Less So

If you’ve written some JavaScript—and if you’re checking out this book, that’s prob-

ably the case—you know that JavaScript lets you get away with just about anything.

You can occasionally leave out semicolons; you can use brackets, or not; you can use

the

var

keyword, or not. That sort of looseness is great for getting things working

quickly, but at the same time, it’s frustrating. It makes ﬁnding bugs tricky at times,

and working across browsers can be a nightmare.

PHP is not quite as loose as JavaScript, so it makes you learn a little more structure

and tighten up your understanding of what’s going on as your program is constructed

and then run. That’s a good thing, because it will end up making you tighten up your

JavaScript skills, too. And, perhaps best of all, PHP’s stodgy consistency makes it

easier to learn. It gives you ﬁrm rules to hang on to, rather than lots of “You can do

this…or this…or this…”

So get ready. There is a lot to learn, but everything you learn gives you something

on which to build. And PHP, lets you know right away when there’s a problem. You

won’t need to pop open an error console or keep an eye out for the tiny yellow

warning triangle in Internet Explorer as you do with JavaScript. More often, you’ll

get a nasty error that stops you in your tracks and screams, “Fix me!” And, over

the next couple of hundred pages, you’ll be able to do just that: ﬁx the problems

you’ll run across in typical PHP programs, whether you’ve written those programs

or someone else has.

PHP Is Interpreted

PHP code comes in the form of

scripts

, which are plain-text ﬁles that you create and

ﬁll with code. Whereas HTML uses lots of angle brackets and keywords like html,

head, and ul, PHP uses lots of dollar signs ($) and keywords like mysql_query and

echo. So, HTML and PHP don’t look at all alike. But where they are alike is in the

basic underlying format: they’re both just text. You can open up an HTML document

not just in a web browser, but in Notepad or an integrated development environ

ment (IDE) like Eclipse or even a command-line editor like vi or emacs. The same

is true for PHP: it’s just text. So, get ready; throughout this book, you’ll be typing

words—albeit strange ones, with lots of underscores—and saving those words into

text ﬁles called scripts.

Once you’ve got a script, you let a PHP program interpret that script. The PHP

inter-

preter

is a piece of software on your web server that reads your script and makes

sense of it, giving the web server output and directions about where to go next or

how to handle a user’s form ﬁeld entries. Your script—remember, just a text ﬁle—is

interpreted, one line at a time, every time it is accessed.

This is a bit dierent from languages like Java or C++, which are

compiled

. In those

languages, you also write your code in text ﬁles, but then run a command that turns

those text ﬁles into something else: class ﬁles, binary ﬁles, pieces of unreadable

code that your computer uses.

PHP & MYSQL: THE MISSING MANUAL

WHAT IS PHP?

The beauty of an interpreted language like PHP—and JavaScript, for that matter—is

that you write your code and go. You don’t need a bunch of tools or subsequent

steps. You write PHP, test it out in the browser, and then write some more. It’s fast,

and that usually means it’s pretty fun.

PHP Doesn’t Run in the Browser

There’s one other big dierence between PHP and what you may be used to with

HTML, CSS, and JavaScript. It’s a big dierence, too; in fact, this dierence is such

a big deal that it’s going to aect everything you do when it comes to writing PHP

scripts, getting those PHP scripts to run, and checking them out in a web browser.

So what’s the dierence? It’s this: PHP, unlike HTML or CSS or JavaScript, doesn’t

run entirely in a browser.

What does that mean? Chapter 1 begins to get into the details, but for now, you

just need to know that HTML, JavaScript, and CSS are entirely handled by your web

browser software. Whether you use Internet Explorer, Apple Safari, Google Chrome,

Mozilla Firefox, or Opera, once you have a browser, you have everything you need.

That’s why you can write an HTML document, save it with an extension like .html,

double-click that ﬁle, and voilà: your browser opens (assuming you’ve got things set

up on your computer the right way) and you’re looking at HTML. You can reference

CSS in that HTML ﬁle as well as JavaScript, and the same thing happens. Write code,

save, and open. Pretty easy stu.

With PHP, you’ll need a bit more than that. The PHP interpreter interacts with your

browser but doesn’t run in the browser automatically. In other words, you cannot

simply double-click a PHP script and expect a browser to pop up and handle things.

HTML forms that submit to a PHP script won’t “just work” the way that HTML and

JavaScript do.

Right now, then, you just need to know two things:

• It’s going to take a little more work to get your PHP programs working. You

can’t just write and save a script and then open it the way you can HTML.

Don’t worry; you’ll learn exactly how to get PHP working both locally—on your

computer—and remotely—on a web hosting company’s servers. But it’s going

to take a little more eort.

• It’s not trivial to set up everything you need to run PHP programs on your own

computer—especially once you involve MySQL, too (more on this in just a mo

ment). That’s why Internet Service Providers (ISPs) and web hosting companies

exist! They take care of that sort of thing. So, although it’s possible to do all

your PHP coding on your own machine, it’s a lot more common to write your

scripts and then send them to a remote web server. Sound scary? It’s not…but

it’s important. You’ll spend a good bit of time in this book writing code and

uploading it to a server.

INTRODUCTION

ABOUT THIS

BOOK

PHP is dierent from JavaScript and HTML in some important ways. You’ll get used

to those dierences, but you’ll be a lot less frustrated and confused if you go in

knowing that you’ll have to do some things dierently when it comes to PHP.

What Is MySQL?

MySQL is a database. It stores your information, your users’ information, and anything

else you want to stu into it. But, beyond its ability to store information, MySQL is

popular. In fact, it’s the most popular open-source database system in the world. It

has literally millions of users working with it, ﬁnding and reporting problems, and

testing its limits. And, it has thousands of developers that at some point have helped

improved its code base.

MySQL is essentially a warehouse in which you can store things to be looked up

later. Not only that, MySQL provides you with a really fast mechanism to ﬁnd all that

stu you stuck in the warehouse whenever it’s needed. By the time you’re through

this book, you’ll love MySQL. It will do work that you could never do on your own,

and it will do that work tirelessly and quickly.

It’s also the perfect companion to PHP. It’s easy to install on any system; it doesn’t

take up huge resources like larger commercial oerings such as Oracle’s or IBM’s

products; and its easy to connect to. In fact, you’ll ﬁnd that PHP and MySQL are

perfectly matched, with a ton of easy-to-use functions that let PHP scripts to do

just about anything you can imagine with a MySQL database.

NOTE

There’s actually a lot more nuance to MySQL—and SQL, the language in which you’ll interact with

MySQL—but it’s better to save that for Chapter 4, when you’ve got a little PHP under your belt.

About This Book

PHP is a web-based language, not a program that comes in a box. Tens of thousands

(maybe even hundreds of thousands) of websites have bits of PHP tutorial or instruc

tion on them. That’s great, right? Well, not so much. Those websites aren’t all current.

Some are full of bugs. Some have more information in the comment trails—scattered

amongst gripes, complaints, and lambasting from other programmers—as they do

in the main page. It’s no easy matter to ﬁnd what you’re looking for.

The purpose of this book, therefore, is to serve as the manual that should have been

included when you download PHP. It’s the missing PDF, if you will (or maybe the

missing eBook, if you’re a Kindle or Nook or iPad person). In this book’s pages, you’ll

ﬁnd step-by-step instructions for getting PHP running, writing your ﬁrst program…

and your second program…and eventually building a web application from scratch.

In addition, you’ll ﬁnd clear evaluations of the absolutely critical parts of PHP that

you’ll use every day, whether you’re building a personal blog or a corporate intranet.

PHP & MYSQL: THE MISSING MANUAL

ABOUT THIS

BOOK

NOTE

This book periodically recommends

other

books, covering topics that are too specialized or tangential

for a manual about PHP and MySQL. Careful readers may notice that not every one of these titles is published

by Missing Manual parent company O’Reilly Media. If there’s a great book out there that doesn’t happen to be

published by O’Reilly, this book will still let you know about it.

PHP & MySQL: The Missing Manual

is designed to accommodate readers at every

technical level. The primary discussions are written for advanced-beginner or inter

mediate web authors and programmers. Hopefully, you’re comfortable with HTML

and CSS, and maybe even know a bit of JavaScript. But, if you’re new to all this

Web stu, take heart: special boxes called “Up to Speed” provide the introductory

information you need to understand the topic at hand. If you’re an advanced user,

on the other hand, keep your eye out for similar boxes called “Power Users’ Clinic.”

They oer more technical tips, tricks, and shortcuts for the experienced computer fan.

Macintosh and Windows

PHP and MySQL work almost precisely the same in their Macintosh and Windows

versions. Even more important, you’ll do most of your work by uploading your

scripts and running your database code against a web server. That means that your

hosting provider has to deal with operating system issues; you get to focus on your

code and information.

In the ﬁrst few chapters, you get your system set up to write code and deal with

PHP scripts. Thereafter, you will soon forget about whether you’re on a Macintosh

or using a Windows-based computer. You’ll just be writing code, the same way you

write HTML and CSS. And remember, you’ll soon be uploading your scripts to remote

web servers, so your own computer is only part of the solution.

FTP: It’s Critical

One piece of software that’s absolutely critical is a good FTP client. No matter how

awesome your scripting skills become—and they’re gonna be formidable!—you have

to actually get your scripts to your web hosting server. That’s where FTP comes in:

it’s the means by which a ﬁle on your computer gets placed in just the right location

on a remote server.

NOTE

From the author: Typing in a command-line editor is actually exactly how I work. But then, I’m a

dinosaur, a throwback to days when you had to watch commercials to see primetime TV, and you’d miss emails

because your pocket didn’t buzz every time your boss whisked you a command through the ether.

Today, for most of you, a good text editor and a good graphical FTP client are much better choices. Seriously, my

addiction owns me, and I so badly want to

:wq!

it.

Chapter 1 points you to several great editors, and the fancier ones will have FTP

built right in. If you don’t opt for an integrated solution, a dedicated FTP program

like Cyberduck (

www.cyberduck.ch

) is great, too. You can write a script, throw it

online, and test it all with a few mouse clicks. So, go ahead and get that FTP program

downloaded, conﬁgured for your web hosting service (which might also be called

your ISP), and ﬁred up. You’re gonna need it.

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PHP与MySQL：全面指南第二版

PHP & MySQL: The Missing Manual

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