1. Lecture 4: Introduction to PHP 3 PHP & MySQL

2. Web based 3-tier architecture

3. 3-tier architecture (application view)

4. Advantages of the 3-tier architecture approach
the ability to separate logical components of an application ensures that applications are easy to manage and understand.
i.e experts can be employed that specialise in one of the layers e.g. user interface design
because communication can be controlled between each logical tier of an application, changes in one tier, for example, the database access tier, do not have to affect the client component
e.g. a change from one DBMS to another would only require a change to the component in the data access layer with little or no effect on the business/logic (middle) or UI layer.
specific tools and technologies suited to each layer can be deployed (and may evolve at a different pace) .

5. Web based 3-tier architecture: tools & technologies
Presentation tier – Browser / custom client, Client Side Scripting (JavaScript, ActionScript, VBScript etc.), Applets.
Logical Tier – Web Server (Apache, IIS, Websphere etc.); Scripting Languages (PHP, Perl etc.), Programming Languages (Java, C, C# etc), Application Frameworks (Ruby on Rails etc.)
Data Tier – Database Management System (DBMS) (Oracle, MySQL, SQL Server, DB2 etc.), XMLDB

6. Using MySQL in the persistence tier:
MySQL Strengths
High performance
benchmarks very well against commercial dbs
Low-cost
no cost under open source licence
Easy to configure and learn
easy to set up, SQL compliant
Portable
Linux, Unix and Windows versions
Open Source
source code available for modification

7. Tools to create a simple web-editable database
QSEE
MySQL client (or PHPMyAdmin)
PHP Script

8. Define ER model
in QSEE
Generate SQL
Create Database
MySQL
Write Script to
process DB

9. QSEE Multi-case diagramming tool Entity-Relationship Diagrams
All UML diagrams ++
Entity-Relationship Diagrams
Generates SQL for various targets (including MySQL 4.0)
Implements relationships automatically
1- many : adds primary key on 1-side as columns in the many side to make foreign keys
Many-many : adds an new link table with the primary keys from both sides as foreign keys (and a joint primary key)
Dependent (weak) entities : foreign key becomes part of the primary key
Sets up the appropriate integrity constraints
Action on delete and update for foreign keys

10. GUI interface to MySQL server (shares)
PHPMyAdmin
GUI interface to MySQL server (shares)
GUI runs on stocks (the PHP server)
Full access to a database for
Creating tables
Added data
Browsing the data
Import and Export of tables…
Execute SQL queries (DML) or definitions (DML)
But ..

11. PHPMyAdmin Interface

12. Command line MySQL
Generated SQL comments are rejected by PHPMyAdmin
login to shares directly using putty
change directory to your project directory
Enter:
mysql –p
use database
source proj.sql

13. Command line MySQL

14. PHP/MySQL a simple example (1):
DB Library - Table Book id
title
author 1
MySQL in Nutshell
Dyer 2
PHP and MySQL
Ullman 3
Javascript
Smith

15. PHP/MySQL a simple example (2):
// set up server, username, password & database
$host="localhost"; // would be "shares" in cems
$un="root"; // would be unix user in cems
$pw=""; // would be original cems passsword
$db="Library"; // would be unix user name
// connect to the mysql server
mysql_connect($host,$un,$pw);
// select the database
@mysql_select_db($db) or die( "Unable to select database");

16. PHP/MySQL a simple example (3):
// build the query
$query="SELECT * FROM book";
// run the query
$result=mysql_query($query);
// count the rows returned
$num=mysql_numrows($result);
// close the connection
mysql_close();

17. PHP/MySQL a simple example (4):
// run a loop outputting one row at a time
while ($i < $num) {
$id=mysql_result($result,$i,"id");
$title=mysql_result($result,$i,"title");
$author=mysql_result($result,$i,"author");
echo "<p>id: $id<br/>Title: $title<br/>Author: $author</p>";
$i++; }
?>

18. PHP/MySQL a simple example (5):