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Transcript
Creating Dynamic
Web Pages Using
PHP and MySQL
CS 320
Review:
Dynamic vs. Static Web Pages
Static Web page
Developer specifies contents when he/she creates
the Web page
Contents do not change based on user inputs
Dynamic Web page
Content varies based on:
User inputs
Data retrieved from external sources such as databases
Review: Web/Database Architecture
2. Request for Web page
that requires database data
1. Request for Web page that
requires database data
Network
5. Web page HTML file
containing database data
downloaded to client
Web server
3. Runs a program
that makes a data
request
4. Data
response
Database
6. Web page HTML file
downloaded to client
Web browser
What is a PHP page?
Text file with a .php extension
Contains HTML tags and elements
Also contains embedded PHP commands
that the Web server processes to create
dynamic content
Why use PHP?
PHP uses a similar coding style to other server-side
scripting languages (ASP, JSP, Cold Fusion)
With a PHP, you can first create a static Web page,
then add the commands for dynamic processing
If you know how to create a PHP, you won’t find it difficult
to learn how to use one of these alternate technologies
Separates design and program commands (somewhat)
Widely used server-side technology
Open source and free
Supports many databases
Running PHP on a Web Server
Web server must support PHP processing
You must have privileges to save pages in
the Web server folder structure
CS 320 Web Development
Environment
Create PHPs using Dreamweaver
Upload to the class Web server for testing
Map
a drive to a specific folder
Save your files in a folder on the server
Test your PHPs using a specific URL
CS 320 Test Environment
Map a drive to
\\leela.cs.uwec.edu\CS320$
Save files to your folder in the Students
folder
URL for testing:
http://leela.cs.uwec.edu/CS320/Students/YOU
RUSERNAME/filename.php
Creating PHPs and PHP Syntax
PHP commands are embedded within an
HTML document
Document
must be saved with a .php
extension
Place PHP script commands within
delimiters:
<?php PHP commands ?>
How are PHP Commands
Processed?
Commands within the <?php … ?> block are
processed on the server before sending the page back
to the user's browser
The code isn’t sent to the browser – only the results of the code
Users can’t View Source to see the code
You can’t open a PHP file directly in a browser to run the PHP
commands (as you can do with JavaScript)
A web server is needed to process PHP commands
General PHP Syntax Notes
Every command line must end with ;
Comment statements:
echo
Displays a dynamic value on the Web page
Supports basic programming constructs:
// single line
/* block of comments */
Variables
If/then statements
Loops
Functions
Assumption: You have learned basic programming concepts
in a previous course
Example PHP
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=utf-8" />
<title>CS 320 - Hello World</title>
</head>
<body>
<p>Hello World! Today's date is:
<?php echo date("m/d/y"); ?></p>
</body>
</html>
Using PHP Variables
Variable names start with $
Data types include:
Booleans (true/false)
Integers
Floating point numbers
Text strings
Arrays
Objects
PHP will make conversions as needed to make data type
match the assigned value
Using PHP to Retrieve Data
From a MySQL Database
Steps:
Improve PHP's error messages
1.
2.
3.
4.
5.
6.
Connect to the MySQL server
Select the MySQL database
Send the query to MySQL and store the results
Retrieve the number of rows that were returned
Close the connection to MySQL
Display the results
Improving MySQL's Error
Messages
Add the following as the first line in all of
your PHP pages:
<?php error_reporting(E_ALL); ?>
Connecting to the server and
selecting the database
Database server
Username
Password
<?php
//Connect to the MySQL database
mysql_connect("dario.cs.uwec.edu","CS320_Student","C4361$")
or die("Could not connect to MySQL.
The reported SQL error is:<br />" . mysql_error());
//Specify the database
mysql_select_db("CS320_Student")
or die("Could not connect to the database.
The reported SQL error is:<br />" . mysql_error());
?>
Database within the user schema
In PHPs, you need to use the central DB
server
Web
server can't access your local database
Specifying the query, storing the
result, closing the connection:
<?php
//Steps to connect to the server and select the database
//Specify the query
$query = "SELECT prod_id, prod_desc, prod_cost, prod_price FROM
candy_product";
//Store the result
$result = mysql_query($query)
or die("SQL Error: <b>" . mysql_error() . "</b><br />");
//Close the connection
mysql_close();
?>
Notes:
Use your local DB to test queries, then copy/paste
them into your PHPs
Don't use hard returns to format your queries!
Formatting queries on multiple
Concatenation
operator
lines:
<?php
//Connect to the MySQL database
mysql_connect("dario.cs.uwec.edu","CS320_Student","C4361$")
or die("Could not connect to MySQL.
The reported SQL error is:<br />" . mysql_error());
//Specify the database
mysql_select_db("CS320_Student")
or die("Could not connect to the database.
The reported SQL error is:<br />" . mysql_error());
//Specify the query
$query = "SELECT prod_id, prod_desc, prod_cost, prod_price " .
"FROM candy_product";
//Store the result
$result = mysql_query($query)
or die("SQL Error: <b>" . mysql_error() . "</b><br />");
?>
Displaying the Data
Variable storing a row of retrieved data
<table border="4" cellpadding="3" cellspacing="1">
<tr><th>Product ID</th>
<th>Description</th><th>Cost</th><th>Price</th></tr>
<?php while ($row = mysql_fetch_array($result)) { ?>
<tr> <td><?php echo $row["prod_id"] ?></td>
<td><?php echo $row["prod_desc"] ?></td>
<td>$<?php echo $row["prod_cost"] ?></td>
<td>$<?php echo $row["prod_price"] ?></td>
</tr>
<?php } ?>
</table>
Database field name
