1. Web-Database Integration
Week 7
LBSC 690
Information Technology

2. Agenda
Questions
E-R Modeling
PHP
Mythical person-month
Midterm review

3. Key Ideas Databases are a good choice when you have
Lots of data
A problem that contains inherent relationships
Design before you implement
This is just another type of programming
The mythical person-month applies!
Join is the most important concept
Project and restrict just remove undesired stuff

4. Getting Started with E-R Modeling
What questions must you answer?
What data is needed to generate the answers?
Entities
Attributes of those entities
Relationships
Nature of those relationships
How will the user interact with the system?
Relating the question to the available data
Expressing the answer in a useful form

5. “Project Team” E-R Example
manage-role 1 M
member-of 1
student
team 1 M
creates
human
implement-role 1 1
needs M
client
project d
php-project
ajax-project

6. Components of E-R Diagrams
Entities
Types
Subtypes (disjoint / overlapping)
Attributes
Mandatory / optional
Identifier
Relationships
Cardinality
Existence
Degree

7. Making Tables from E-R Diagrams
Pick a primary key for each entity
Build the tables
One per entity
Plus one per M:M relationship
Choose terse but memorable table and field names
Check for parsimonious representation
Relational “normalization”
Redundant storage of computable values
Implement using a DBMS

8. 1NF: Single-valued indivisible (atomic) attributes
Split “Doug Oard” to two attributes as (“Doug”, “Oard”)
Model M:M implement-role relationship with a table
2NF: Attributes depend on complete primary key
(id, impl-role, name)->(id, name)+(id, impl-role)
3NF: Attributes depend directly on primary key
(id, addr, city, state, zip)->(id, addr, zip)+(zip, city, state)
4NF: Divide independent M:M tables
(id, role, courses) -> (id, role) + (id, courses)
5NF: Don’t enumerate derivable combinations

9. Normalized Table Structure
Persons: id, fname, lname, userid, password
Contacts: id, ctype, cstring
Ctlabels: ctype, string
Students: id, team, mrole
Iroles: id, irole
Rlabels: role, string
Projects: team, client, pstring

10. Ways of Generating Web Pages
Static: Written in a markup language
HTML, XML
Dynamic: Generated using a program
Common Gateway Interface [Perl] (.cgi)
Java servlets
Dynamic: Generated from a database
Cold Fusion (.cfm)
PHP (.php)

11. Why Database-Generated Pages?
Remote access to a database
Client does not need the database software
Serve rapidly changing information
e.g., Airline reservation systems
Provide multiple “access points”
By subject, by date, by author, …
Record user responses in the database

12. Issues to Consider Benefits Costs Multiple views Data reuse Scalable
Access control
Costs
Formal modeling
Complex (learn, design, implement, debug)
Brittle (relies on multiple communicating servers)
Not crawlable

13. Downside Brittle Complex Formally modeled Depends on multiple servers
Learning, design, implementation, debugging
Formally modeled

14. Three Ways to Serve Data
Microsoft
Web Server
.mdb
Microsoft
Access
DBMS
Web
Browser
Cold Fusion
Server
mysql
database
mysql
DBMS
PHP-enabled
Web Server

15. Microsoft “Data Access Pages”
Displays database content on Web pages
Not very useful for changing database content
Drag-and-drop design in Microsoft Access
“Reports” are designed for printing
“Pages” are designed for the Web
Requirements:
Microsoft Web Server (not Apache)
IE 5 or higher Web browser (not Firefox)
“Office Web Components” on client machine
IE 7 fails gracelessly without them!

16. Data Access Page Example
Design
View:
Web
Page:

17. Server-side Programming Interchange Language Client-side Programming
Relational normalization
Structured programming
Software patterns
Object-oriented design
Functional decomposition
Client Hardware
(PC, Unix)
(MySQL)
(PHP)
(HTML, XML)
(JavaScript)
(IE, Firefox)
(PC)
Business
rules
Interaction
Design
Interface
Web Browser
Server-side Programming
Interchange Language
Client-side Programming
Database
Server Hardware

18. PHP Programming Environments
You need three systems on the same server:
PHP (programming language)
MySQL (DBMS)
Apache (Web server)
WampServer (for PC)
Includes GUI tools
OTAL (Sun Unix) supports Web deployment
Requires a text editor (e.g., emacs) or FTP

19. Making PHP ----- HTML stuff ----- <?php ----- PHP stuff ----- ?>
stuff---/xxxxx.php

20. WampServer Download and install Make sure the server is working
From
Make sure the server is working
Point a Web browser at
Select phpinfo.php
Error reporting on? MySQL listed?
Test the connection to MySQL
Run mysql_test.php (“Resource id #2” indicates ok)
<?php
echo mysql_connect(‘localhost’, ‘root’, ‘’);
?>

21. Connecting PHP to MySQL
On WAMP:
$dbc=mysql_connect (‘localhost’, ‘userid’, ‘password’);
On OTAL:
$dbc=mysql_connect(‘:/export/software/otal/mysql/run/mysqld.sock’,
‘userid’, ‘password’);

22. Create a MySQL Database
“root” user creates database + grants permissions
Using the WAMP console (or mysql –u root –p)
root has no initial password; just hit <enter> when asked
By the system administrator on OTAL (otal.umd.edu)
CREATE DATABASE project;
GRANT SELECT, INSERT, UPDATE, DELETE, INDEX, ALTER, CREATE, DROP ON project.* TO IDENTIFIED BY ‘bar’;
FLUSH PRIVILEGES;
Start mysql
MySQL console for WAMP, ssh for OTAL
mysql –u foo –p bar
Connect to your database
USE project;

23. Creating Tables To delete: DROP TABLE contacts;
CREATE TABLE contacts (
ckey MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT,
id MEDIUMINT UNSIGNED NOT NULL,
ctype SMALLINT UNSIGNED NOT NULL,
cstring VARCHAR(40) NOT NULL,
FOREIGN KEY (id) REFERENCES persons(id) ON DELETE CASCADE,
FOREIGN KEY (ctype) REFERENCES ctlabels(ctype) ON DELETE RESTRICT,
PRIMARY KEY (ckey)
) ENGINE=INNODB;
To delete: DROP TABLE contacts;

24. Populating Tables To empty a table: DELETE FROM ctlabels;
INSERT INTO ctlabels
(string) VALUES
('primary '),
('alternate '),
('home phone'),
('cell phone'),
('work phone'),
('AOL IM'),
('Yahoo Chat'),
('MSN Messenger'),
(‘other’);
To empty a table: DELETE FROM ctlabels;

25. “Looking Around” in MySQL
SHOW DATABASES;
SHOW TABLES;
DESCRIBE tablename;
SELECT * FROM tablename;

26. Structured Query Language
DESCRIBE Flight;

27. Structured Query Language
SELECT * FROM Flight;

28. Structured Query Language
SELECT Company.CompanyName, Company.CompanyPhone, Flight.Origin, Flight.DepartureTime
FROM Flight,Company
WHERE Flight.CompanyName=Company.CompanyName
AND Flight.AvailableSeats>3;

29. Statements in PHP Sequential Conditional Loop
{…; …;…;}
Semicolons are required at the end of every statement
Conditional
if (3==i) {…} else {…}
Loop
for ($i=0; $i<10; $i++) {…}
while ($row=mysql_fetch_array(…)) {…}
foreach ($array as $key => $value) {…}
Braces are optional around a single statement

30. Variables Name starts with a $ Hold a value
Case sensitive (assume everything could be!)
Hold a value
Number (integer, float)
String (double quotes, \ escape character)
TRUE, FLASE
NULL
Need not be declared (automatically “cast”)

31. Operators in PHP Arithmetic operators Logical operators
+ - * /
Logical operators
< <= == != >= > && || !
String operator .

32. Arrays in PHP A set of key-element pairs
$days = array(“Jan”->31, “Feb”=>28, …);
$months = explode(“/”, “Jan/Feb/Mar/…/Dec”);
$_POST
Each element is accessed by the key
{$days[“Jan”]}
$months[0];

33. Functions in PHP Declaration Invoking a method
function multiply($a, $b=3){return $a*$b;}
Invoking a method
$b = multiply($b, 7);
All variables in a function have only local scope
Unless declared as global in the function

34. Using PHP with (X)HTML Forms
<form action=“formResponseDemo.php”, method=“post”>
<input type=“text”, name=“ ”, value=“<?php echo $ ?>”, size=30 />
<input type=“radio”, name=“sure”, value=“yes” /> Yes
<input type=“radio”, name=“sure”, value=“no” /> No
<input type=“submit”, name=“submit”, value=“Submit” />
<input type=“hidden”, name=“submitted”, value=“TRUE” />
</form>
if (isset($_POST[“submitted”])) {
echo “Your address is $ .”;
} else {
echo “Error: page reached without proper form submission!”; }

35. <?php # Script 8.1 - mysql_connect.php
// Set the database access information as constants.
DEFINE ('DB_USER', 'tester');
DEFINE ('DB_PASSWORD', 'tester');
DEFINE ('DB_HOST', 'localhost');
DEFINE ('DB_NAME', 'sitename');
// Make the connection.
$dbc (DB_HOST, DB_USER, DB_PASSWORD) OR die ('Could not connect to MySQL: ' . mysql_error() );
// Select the database.
@mysql_select_db (DB_NAME) OR die ('Could not select the database: ' . mysql_error() );
// Create a function for escaping the data.
function escape_data ($data) {
// Address Magic Quotes.
if (ini_get('magic_quotes_gpc')) {
$data = stripslashes($data); }
// Check for mysql_real_escape_string() support.
if (function_exists('mysql_real_escape_string')) {
global $dbc; // Need the connection.
$data = mysql_real_escape_string (trim($data), $dbc);
} else {
$data = mysql_escape_string (trim($data));
// Return the escaped value.
return $data;
} // End of function.
?>

36. <?php # login.php
// Send NOTHING to the Web browser prior to the session_start() line!
// Check if the form has been submitted.
if (isset($_POST['submitted'])) {
require_once ('../mysql_connect.php'); // Connect to the db.
$errors = array(); // Initialize error array.
// Check for an address.
if (empty($_POST[' '])) {
$errors[] = 'You forgot to enter your address.';
} else {
$e = escape_data($_POST[' ']); }
// Check for a password.
if (empty($_POST['password'])) {
$errors[] = 'You forgot to enter your password.';
$p = escape_data($_POST['password']);

37. if (empty($errors)) { // If everything's OK.
/* Retrieve the user_id and first_name for that /password combination. */
$query = "SELECT user_id, first_name FROM users WHERE ='$e' AND password=SHA('$p')";
$result ($query); // Run the query.
$row = mysql_fetch_array ($result, MYSQL_NUM); // Return a record, if applicable.
if ($row) { // A record was pulled from the database.
// Set the session data & redirect.
session_name ('YourVisitID');
session_start();
$_SESSION['user_id'] = $row[0];
$_SESSION['first_name'] = $row[1];
$_SESSION['agent'] = md5($_SERVER['HTTP_USER_AGENT']);
// Redirect the user to the loggedin.php page.
// Start defining the URL.
$url = ' . $_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']);
// Check for a trailing slash.
if ((substr($url, -1) == '/') OR (substr($url, -1) == '\\') ) {
$url = substr ($url, 0, -1); // Chop off the slash. }
// Add the page.
$url .= '/loggedin.php';
header("Location: $url");
exit(); // Quit the script.
} else { // No record matched the query.
$errors[] = 'The address and password entered do not match those on file.'; // Public message.
$errors[] = mysql_error() . '<br /><br />Query: ' . $query; // Debugging message.
} // End of if (empty($errors)) IF.
mysql_close(); // Close the database connection.
} else { // Form has not been submitted.
$errors = NULL;
} // End of the main Submit conditional.

38. // Begin the page now.
$page_title = 'Login';
include ('./includes/header.html');
if (!empty($errors)) { // Print any error messages.
echo '<h1 id="mainhead">Error!</h1>
<p class="error">The following error(s) occurred:<br />';
foreach ($errors as $msg) { // Print each error.
echo " - $msg<br />\n"; }
echo '</p><p>Please try again.</p>';
// Create the form.
?>
<h2>Login</h2>
<form action="login.php" method="post">
<p> Address: <input type="text" name=" " size="20" maxlength="40" /> </p>
<p>Password: <input type="password" name="password" size="20" maxlength="20" /></p>
<p><input type="submit" name="submit" value="Login" /></p>
<input type="hidden" name="submitted" value="TRUE" />
</form>
<?php
include ('./includes/footer.html');

39. Server-side Programming Interchange Language Client-side Programming
Relational normalization
Structured programming
Software patterns
Object-oriented design
Functional decomposition
Client Hardware
(PC, Unix)
(MySQL)
(PHP)
(HTML, XML)
(JavaScript)
(IE, Firefox)
(PC)
Business
rules
Interaction
Design
Interface
Web Browser
Server-side Programming
Interchange Language
Client-side Programming
Database
Server Hardware

42. Ajax Applications Google Maps Google Suggest Sajax Tables Sajax
Google Suggest
Sajax Tables
Sajax

43. Discussion Point: Mythical Person-Month
Why is software development different from manufacturing car?
If it would take one person three months, why does it take four people SIX months?

44. Trading People and Months is Hard
Sequential constraints
Communication
Training

45. Estimating Completion Time
Rules of thumb
1/3 specification
1/6 coding
1/2 test planning, testing, and fixing!
Add time for coding to learn as you go, but don’t take time away from the other parts!
Reread the section on “gutless estimating” if you are tempted

46. The Grand Plan Networking HTML/XML Multimedia Computers HCI Search CMC
LBSC
733
HCI
Search
CMC
Web
Life Cycle
Policy
LBSC
795
LBSC
795
Quiz
LBSC
790
Databases
Programming
Web Databases
Midterm
LBSC
793
Project
Final
INFM
718N

47. The Midterm 1 hour and 15 minutes
Second half of class: project team meetings
Quiz/homework should be good preparation
A variety of question types
Some questions will require computer use
Lots of prior exams are available
Some have solutions available
Open book/notes/Internet/mind/…
Just don’t get help from another person

48. Computer Systems Hardware Software Types of hardware Storage hierarchy
Moore’s law
Software
Types of software
Types of interfaces

49. Networks Types of Networks Packet Switching
LAN, WAN, Internet, Wireless
Packet Switching
Ethernet, routers, routing tables
Layered Architecture and protocols
TCP/UDP
IP address/domain name

50. Structured Documents The Web XML HTTP, HTML, URL My Browser
A server that sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server. Proxy servers have two main purposes:
Improve Performance: Proxy servers can dramatically improve performance for groups of users. This is because it saves the results of all requests for a certain amount of time. Consider the case where both user X and user Y access the World Wide Web through a proxy server. First user X requests a certain Web page, which we'll call Page 1. Sometime later, user Y requests the same page. Instead of forwarding the request to the Web server where Page 1 resides, which can be a time-consuming operation, the proxy server simply returns the Page 1 that it already fetched for user X. Since the proxy server is often on the same network as the user, this is a much faster operation. Real proxy servers support hundreds or thousands of users. The major online services such as Compuserve and America Online, for example, employ an array of proxy servers.
Filter Requests: Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites.
My Browser

51. Multimedia Compression, compression, compression Streaming
Image: lossy vs loseless
Video: frames are alike
Speech: voice predictable
Music: masking
Streaming
Media Sever
Buffer
Internet

52. Programming Input Output Programming languages Control structures ?
Machines require specific instructions
Humans require high-level abstraction
Control structures
Sequential execution
Conditional
Iteration
Javascript
Input
Output ?

53. Databases Structured information Normalized tables (relations)
Field->record->table->database
Primary key
Normalized tables (relations)
Remove redundancy, inconsistency, error
Easy update, search
Join links tables together
Through foreign key
Access provides visual operations

54. Web-Database Integration
Microsoft “Data Access Pages”
Server-side database integration
Ajax
Mythical person-month