This document provides an outline for a course on databases and database users. It introduces key concepts about databases including what a database is, database properties, database management systems, actors involved with databases like administrators and designers, advantages of databases over file systems, and common database applications. The outline covers topics that will be taught like introduction to PHP and MySQL, how to code applications with databases, and how to perform common tasks with databases.

1. Course Outline,
Database & Database Users
Lecture 01
National IT ProfessionalsAssociation of Afghanistan
NITPAA
Lecturers:
M.Zalmai Rahmani & Parwiz Danyar

2. Course Outline
 Introduction to PHP & MySQL
 How to code a PHP application
 Introduction to relational databases and MySQL
 How to use PHP with a MySQL database
 How to test and debug a PHP application
 How to work with form data
 How to code control statements
 How to work with strings and numbers
 How to work with dates
 How to create and use arrays
 How to work with cookies and sessions
 How to create and use functions

3. Tools
 WAPM, XAMP and MAMP
http://www.wampserver.com/en/
https://www.apachefriends.org/download.html
https://www.mamp.info/en/downloads/
 MySQL Workbench
https://www.mysql.com/products/workbench/
 Notepad++ or any Editor
https://notepad-plus-plus.org/download/v7.6.3.html
https://www.sublimetext.com/

4. Database Applications
Banking:
For customer information, accounts, loans and banking transactions.
Universities:
For student information, course registrations, and grades.
Sales:
For customer, product, and purchase information.
Airlines:
For reservations and schedule information.

5. Database Applications
Credit card transactions:
For purchases on credit cards and generation of monthly statements
“printed record of account activity”.
Human resources:
For information about employees, salaries, payroll taxes and benefits, and
for generation of pay checks “salary”.
Telecommunication:
For keeping records of calls made, generating monthly bills, maintaining
balances on prepaid calling cards, and storing information about the
communication network.

6. Database Applications
Finance:
For storing information about sales, and purchases of financial instruments
such as stocks and bonds.
Manufacturing:
For management of supply chain and for tracking production of items in
factories, inventories of items in warehouses/stores, and orders for items.

7. Databases play a critical role in almost all areas in which
computers are used!
Brainstorming Summary

8. What is database?
A database is a collection of related data.
By data, we mean known facts that can be recorded and that have implicit
meaning.

9. Database Properties
Represents some aspect of the real world that is called the miniworld.
Changes to the miniworld are reflected in the database.
Is a logically coherent collection of data with some inherent meaning.
A random assortment of data cannot correctly be referred to as a database.
Is designed, built, and populated with data for a specific purpose.

10. Size & Complexity of a Database
A database can be of any size and complexity
• Example for a small database:
Personal DB with addresses with only a few hundred records (each with a
simple structure)
• Example for a large database:
Amazon.com: with more than 20 million of books, CDs, eBooks,
magazines, journals and etc. In a DB with the size of 2 terabytes

11. Database Management Systems
(DBMS)
A Database Management System (DBMS) is a collection of interrelated data
and set of programs to access those data.
• The collection of data, usually referred to as the database, contains
information related to an enterprise.
Is a collection of programs that enables users to create and maintain a
database.

12. Database Management Systems
(DBMS)
DBMS fulfils(Do) different purposes:
• Defining : Specifying the data types, structures, and constraints for the data
to be stored in the database.
• Constructing : Process of storing the data itself on some storage medium
that is controlled by the DBMS.
• Manipulating : Adding, Updating, Deleting ….
• Sharing databases among various users and applications

13. (DBMS)
MS Access
MySQL (Open Source)
SQL-Server (Microsoft)
Oracle
PostgreSQL
FoxPro
SQLite

14. Application Program /
Database System
An application program accesses the database by sending queries or
requests to the DBMS.
• A query (question, inquiry) is the interaction with the database, e.g.
retrieving or manipulating data.
Database System
• The database, the DBMS software, and the application program together
are called a database system.

15. Overview

16. Example of a Database System
UNIVERSITY database
• Defining the database: we must specify the structure of the records of each
file by specifying the different types of data elements to be stored in each
record .
• Constructing the database: we store data to represent each student,
course, section, grade report, and prerequisite as a record in the appropriate
file
• Manipulating the database: Querying and updating

17. Characteristics of the Database
A number of characteristics distinguish the database approach from the
traditional approach of programming with files :
• Self Describing nature of the database
Database system contains not only the database itself but also a complete
definition or description of the database structure and constraints.

18. Characteristics of the Database
Data Abstraction
• Allows program-data independence and program-operation independence
MultipleViews of the Data
• Some users may not need to be aware of whether the data they refer to is
stored or derived
• One user of the database may be interested only in the transcript of each
student;
• A second user, who is interested only in checking that students have taken all
the prerequisites of each course they register for

19. Characteristics of the Database
Sharing of Data and MultiuserTransaction Processing
• ConcurrencyControl to manage transactions
A transaction is an executing program or process that includes one or more
database accesses, such as reading or updating of database records

20. Actors on the scenes
What roles do people take around a database system?
• Database Administrators
• Database Designers
• End Users
• Application Programmers (Software Engineers)

21. Actors on the scenes
Database Administrators
• When the database is designed and implemented it is handed over to the DB
administrator
• person responsible for the DB during its lifetime
• management of user accounts, hardware resources, backups, etc.

22. Actors on the scenes
Database Designers
• The database designers conceptually design and implement the DB
• Analyze requirements for the DB
• Gathering of information about the application field
• Conceptual schema. (conceptual = of an idea or concept)
• Choice of DBMS

23. Actors on the scenes
End Users
• The people who will use the DB when it is finished
• Normally little technical knowledge
• Use the DB
Application Programmers
• Programmers that write programs that use the DB
• Programmers of a graphical user interface (GUI) for the database

24. Workers behind the scenes
People who are working behind the database scenes are as:
• DBMS system designers and implementers
• Design and implement the DBMS modules and interfaces as a software
package.
Tool developers
• Design and implement tools—the software packages that facilitate database
modelling and design, database system design, and improved performance.
Operators and maintenance personnel
• Responsible for the actual running and maintenance of the hardware and
software environment for the database system.

25. Advantages of using the DBMS
Controlling redundancy
Providing Storage Structures and SearchTechniques for Efficient Query
Processing
Providing Backup and Recovery
Providing Multiple User Interfaces
Representing Complex Relationships among Data
Enforcing Integrity Constraints
Permitting Inference and Actions Using Rules

26. DBMS VS. File Systems

27. Why don’t store on plain files?
Consider part of a savings-bank enterprise that stores information about all
customers and saving accounts.
• We need separate application programs that manipulate the files.
• A program to debit or credit an account
• A program to add a new account
• A program to find the balance of an account
• A program to generate monthly statements

28. File Systems

29. Advantages of using file
systems
We would rather use plain files and develop additional software tools, if:
• The database is simple
• The actions on the data are simple
• No multi-user environment
Example: private address book, data can be even “stored” on paper

30. Disadvantages of using file
systems
Data redundancy and inconsistency:
• Since in File Systems we store all information in different files, so the same
information maybe duplicated in several files.
• Redundancy leads to higher storage and access cost.
• Redundancy also leads to data inconsistency

31. Disadvantages of using file
systems
Difficulty in accessing data
• What happen if someone asks about list of all customers who live in a special
city “kabul”, Since the original system did not predict this kind of list with
mentioned criteria
• File Systems do not allow needed data to be retrieved in a convenient and
efficient manner.
Data Isolation:
• Because data are scattered in various files, and files maybe in different
formats, writing new application programs to retrieve the needed data is not
that much easy.

32. Disadvantages of using file
systems
Problems
• Consider a program to transfer 100$ from accountA to account B.
Constrains:
If a system failure or crush occurs during the execution of the transfer.
Possibility:
100$ remove from accountA, but not added to account B.
• It is essential to database consistency that either both the debit and credit
occur, or that neither occur.

33. Disadvantages of using file
systems
Concurrent access exception
• Uncontrolled multi-user access can have undesirable results!
• Consider bank accountA, has 500$. If two customers at the same time
withdraw (one 50$ and the other 100$) from accountA, the result of the
concurrent executions may leave the account in an incorrect state.
Security Problems
• Data should not be accessible for all users.
• No Mechanism for giving certain privileges to certain users.
• No mechanisms for user authorization and encryption in file-processing
system.

34. Advantages of database
systems
Fast, complex queries on data are possible:
• Example:
We would like to know the names of all employees who live in Kabul and
have a salary higher than the average salary.
• It is not easy/can take a lot of time to extract this information from a file.
• It is even more difficult/impossible to “link” data that is stored across several
isolated files.

35. Advantages of database
systems
Redundancy control and consistency control
• Example:
Both, university administration and individual departments store data
about students in isolated files
• Same data is stored several times (=redundancy)
• More storage space necessary
• Difficult to maintain consistency (for example if
Administration updates address of student, but it is not updated in the files
of department)

36. Advantages of database
systems
Support of multi-user environment
• Uncontrolled multi-user access can have undesirable results!
Example:
if userA and user B read a file at the same time, userA writes data into the
file and stores it, user B writes data and stores it data of userA is
overwritten!
Database Systems provide mechanisms to control multiuser access
(concept of “Transactions”)

37. Advantages of database
systems
Prevention of data loss
• Power failure, hardware/software failure can result in loss of data
• Database Systems provide more sophisticated recovery components to
backup and restore data than File Systems

38. Advantages of database
systems
Security Issues
• Often we would like to control which users get access to what parts of the
data (read or even manipulate data)
• Database systems provide mechanisms for user authorization and
encryption

39. Disadvantages of database
systems
Complex, expensive software and hardware
Skilled professionals and user training necessary
Therefore high start-up costs