Download Intro to Databases

Introduction to
Databases
CS 320
Basic Web Architecture
2. Request for
Web page
1. Request for
Web page
Network
3. Web page HTML file
downloaded to client
Web server
4. Web page HTML file
downloaded to client
Web browser
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
Examples of Web/Database
Applications








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Banking
Airline reservation and scheduling
University registration
Credit card transactions and billing
Sales purchasing & inventory
Ecommerce
Manufacturing supply chain management
Human resources: payroll, benefits
Insurance
…
Specific Examples of Dynamic Web
Pages That Use Databases
D2L
 Amazon.com
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Before you can create dynamic Web pages that
retrieve database data, you must first
understand databases!
What is Data?
 Numbers
 Characters
 Dates
 Binary objects
 Images
 Sound clips
 Video clips
Data Management

"Real" computer applications tend to have:
 Large
volumes of data
 Different types of data
 Data with complex relationships

It is difficult to manage data in real
applications using data files
File-Based (non-database)
Approach to Data Management
 File-based
 Decentralized
 Each application has its own data file(s)
Data
File 1
Application
1
Data
File 2
Application
2
Example Data File
Problems with file based
approach?
Duplicate data
 Redundant data

 Becomes
inconsistent over time
Requires custom programs to create,
update, and retrieve data from files
 Concurrent access issues
 Security

Database Approach to Data
Management
 Data is viewed as a shared organizational resource
 Centralized
 All applications interact with a single centralized
database
Application
1
Database
Application
2
...
What is a Database?

Components:
 Data
files
 Database Management System (DBMS)
Database
Application
1
Data
Files
DBMS
Application
2
...
What is a DBMS?
 Set of programs that perform:
 Basic data handling procedures
 Insert, update, delete, retrieve
 Database administration tasks
 Creating users, creating tables, enforcing security,
creating backups, …
 Major players today:
 Oracle, SQL Server, MySQL
Web/Database Development
You must write server-side programs that
interact with the database
 Most ISPs provide a hosting option that
provides server-side program support and
a database

 In
this course, we will be using PHP and the
MySQL DBMS
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
MySQL DBMS

Free
 "Open
source" software
Commonly used for Web applications
 Uses the SQL query language

 Industry
standard
 Used by most major DBMSs
Test Yourself:
What is a DBMS?
a.
b.
c.
d.
A program that stores data
A program that manages and administers
data
A program that runs on the Web server
and creates dynamic Web pages
None of the above
Test Yourself:
What is a DBMS?
a.
b.
c.
d.
A program that stores data
A program that manages and administers
data
A program that runs on the Web server
and creates dynamic Web pages
None of the above
Test Yourself:
What is SQL?
a.
b.
c.
d.
The standard query language for
databases
A free, open-source DBMS
A programming language for creating
dynamic Web pages
None of the above
Test Yourself:
What is SQL?
a.
b.
c.
d.
The standard query language for
databases
A free, open-source DBMS
A programming language for creating
dynamic Web pages
None of the above