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FUNCTIONS ANDSTORED PROCEDURES & FUNCTIONS AND PROTECTING A DBAND PHP
(Chapters 9, 15, 18)
Canned String Functions• Concatenate• Length of a string• Removing leading or trailing spaces• Finding string substrings• Transform string to upper or lower case• Reversing a string• Insert a substring into a string• Right or left padding of a string with a character• Etc.
Canned Numerical Functions• Round• Truncate• Absolute value• Square root• Random value• Etc.
Dates and Times• Now – local date and time from clock• Current timestamp• Currant date• Current time• Extract second, minute, hour, etc.,, from a date• Formatting dates• Adding intervals to dates• Subtract intervals from dates• Returning elapsed period length• Etc.
Specialized Functions• IF (testing an expression for true)• IFNULL (test two expressions and return first or second
based on which is non-null)• COALESCE (test a list of expressions and return first non-
null)
Two ways to use SQL with an Application
• Dynamic SQL• Embedded SQL• Making calls to an SQL based DB
Dynamic SQL• SQL code can be generated at runtime based on
conditions found by the Host application• In particular, to create the appropriate WHERE clauses• The SQL code is put into a Host application string variable• You can use dynamic SQL within a stored procedure
EMBEDDED SQL• SQL is placed inside Host application code• The SQL is processed in a first compilation phase• SQL application uses cursors and INTO statements to
pass values to Host application
Connecting to a DB• PHP:
• mysqli (the i is for improved)• or PDO (PHP Data Objects)
• Java: there are a set of drivers for the various relational databases, including MySQL• The JDBC drivers are very popular and a lot of GUIs use them
• .NET driver
Protecting a MySQL DB• Create and delete databases• Grant specific access rights to groups of users
• Insert, Delete, Select rights on databases• Administration and other users• You can limit a user to access a DB only from a certain IP address
• Separate access rights for altering a schema• Create DBs• Add tables• Change tables• Create views• Create indices• Create triggers
PHP and MySQL
Web Server Database Server
E-mail Server
The Internet
`
Client
`
Client
Continued
Web Server
PHPScript
Database Server
HTTP request
HTTP response`
Web Browser
The MVC pattern
`
Browser
Controllerindex.php
Viewproduct_list.phpproduct_add.php
database_error.php
Modeldatabase.php
product_db.phpcategory_db.php
Data store
HTTPrequest
HTTPresponse
Please install…• PHPStorm – for working with PHP• RubyMine – for Ruby on Rails MVC framework• Intellij IDEA – for Grails MVC framework
PHPStorm & Textbook’s examples• Please install PHPStorm• Go to http://
murach.com/servlet/murach.downloads.DownloadServlet?file=phps_allfiles.zip• Login• Download zip file• Open PHP_allfiles• Make the guitar shop db• Put the project under the xampp (or other) doc root• Run http://localhost/textbook/
PHP & Textbook, continued• Open the index file with PHPStorm
• See page 17 of text• See HTML• See link tag for the CSS file• See the sets of label and input tags that create input boxes• Notice content, data, and buttons in the div tags, which are part of
the CSS code
• Open main.css with PHPStorm, to see CSS
The PHP File• Open display_discount.php file with PHPStorm• Notice that
• The PHP retrieves values from text box, product description, list price, and discount price ($_POST is an array)• This is a built in array• The http POST method is defined in the previous html page
• The PHP code calculates the Discount• Notice that PHP is converting strings to integers• The bottom part of the PHP file uses PHP echo commands to
display the values
Example: PHP embedded in HTML• <?php• // get the data from the request• $first_name = $_GET['first_name'];• $last_name = $_GET['last_name'];• ?>• <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional• ...>• <html xmlns="http://www.w3.org/1999/xhtml">• <head>• <title>Name Test</title>• <link rel="stylesheet" type="text/css" • href="main.css"/>• </head>• <body>• <h2>Welcome</h2>• <p>First name: <?php echo $first_name; ?></p>• <p>Last name: <?php echo $last_name; ?></p>• </body>• </html>
