Intro to PHP

Carl-Erik Svensson

What is PHP?

• PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML*

*Source: http://www.php.net

Why Use PHP?

• Simple, yet powerful scripting tool

• Easily format and display database information

• It is popular

Image Source: http://www.securityspace.com/s_survey/data/man.200709/apachemods.html

The Basics

The Results

• Output from a script goes directly into the HTML that is parsed

• This is what is meant by a ‘dynamic’ webpage

Some Syntax

• Generally C-like• Variables are not strongly typed

Web Applications

• Form processing

• Database manipulation

– Blogs– Forums– Facebook

PHP + MySQL = Sweet

• MySQL is an open source database software solution

• Enables rich web applications when combined with PHP

Image Source: http://www.mysql.com/

Rainfall Application

• Read the contents of a database

• Get the rainfall data

• Parse the results

• Display it

Connecting to a Database

• PHP Has a set of functions that can be used with MySQL

• First step is to setup a link to the desired database

Making a Query

• Once a link is established, querying is easy• Errors for any given function are returned by

mysql_error()

MySQL Result Set

• The value returned by mysql_query() is a reference to an internal data structure

• It can be parsed by various functions

Associative Arrays

• An array that can be indexed by a string• A set of key->value pairs• Very similar to a hash in Perl

PHP foreach

• Similar to the Perl equivalent• Allows iterating through each element of an

array

Put it All Together

The Results

http://128.174.242.224/PHPExamples/rainfall.php

A Slight Improvement

• This was not the exact code we came up with

• I added some titles and a neat trick– Highlight every other row in the table– This makes information more readable

Samples

• USGS Example Rainfall

• EC Awards Committee Scholarship Database

What Else Can PHP Do?

• Command line scripting

• Desktop applications

• Anything

Links

• PHP.net• PHP Manual• MySQL