The document provides an overview of information systems and databases as covered in the HSC course. It discusses different types of information systems and focuses on organizing, storing, and retrieving data with database systems. It describes skills needed to analyze database information systems and provides examples to practice these skills. Finally, it covers topics like database design, data storage and retrieval methods, and some social and ethical issues related to information systems.

1. Mr ZARKOVIC
Information Systems and
Databases

2. Information Systems
 This is the second core topic in the HSC
course i.e. it is compulsory
 The syllabus begins with an overview of
various types of information systems.
 Some of these systems form the basis of
later option stands. For example:
• Transaction processing systems
• Decision support systems

3. Databases
However, the major emphasis of this
topic is on
“… the process of organising, storing
and retrieving data with database
systems and hypermedia.”

4. Skills for Information systems
 For a given example of a database
information system students need to be
able to:
• identify Participants
• identify Data/information
• identify Information technology
• describe the relationship between participants,
data/information and information technology

5. Examples of Information systems
 To practice the above skills, the
syllabus suggests applying the
previous skills to some example
database systems:
• School databases
• RTA
• Video store

6. Examples of Information systems
 If it can be arranged, these systems can
be visited, with students noting down the
participants, data/information, information
technology and describing the various
relationships
 An ‘excursion’ to the school library or to
the administration section of the school is
a cheap and easy (paper-work-wise) way
to accomplish this goal

7. Examples of Information systems
 Alternatively, students may be asked
to research the RTA and the local
video shop in their own time
 Examples should not be limited to
those given in the syllabus - you or
the students may be able to come up
with something localised or relevant
to their experiences

8. Organisation Methods

9. Computer based vs Non-Computer
based
 Students often get fixed on the idea that a
computer based solution is always the most
efficient and most appropriate
 The telephone book is an example of a non-
computer based information system, that is
efficient and sufficient for 99% of people for 99%
of the time
 Compare the length of time it takes to look up a
phone number in a book to the time taken to look
up the same phone number on the internet
 Are there any advantages to using the internet
for this task?

10. Computer based methods for
Organising Data
 There are three choices
• Flat file systems
• Database Management Systems (to
operate ‘relational’ databases)
• Hypermedia
 The work on hypermedia is best held
over until the next topic,
Communication systems or the
Multimedia option

11. Flat File Systems
 These systems store data in a single file
 The data is divided up into columns (called
fields) and rows (called records)
 Data in fields are comprised of characters
and form data of various types:
alphanumeric (‘text’), numeric (including
date, time, currency, etc), boolean (T/F,
Y/N, M/F, etc) and so on
 Any of the simpler database programs –
such as that found with Microsoft Works or
AppleWorks create flat file databases

12. Flat File Systems
 Key field – this field contains data to uniquely
identify every record in the database
 These are also used in relational databases
 Flat file databases are perfectly acceptable for
certain situations
 They can become inefficient and difficult to
manage for large volumes of data. Why?
e.g. a student’s CD/DVD collection is a useful example
to demonstrate ‘data redundancy’ in a flat-file database
system

13. Database Management Systems
(DBMS)
 A DBMS is the software used to
• Create
• Manage, and
• Query
… a database.
 A DBMS is used for more complex
organisation of data, like that commonly
used in a relational database
 It is not a part of the database - the
database is just the collection of data files

14. How a DBMS Works
Database
D
B
M
S
User
Data Base
Management
System

15. Organisation of Relational
Databases
 There are a number of files called tables
(sometimes called entities or relations)
 The columns (fields) of each table are
called attributes
 The rows (records) are known as tuples
 Each table must have a primary key
 Tables are linked by having a field in one
table (foreign key) which is a primary key
field in another table

16. Design of relational databases
 The purpose of the database will play
the major role in determining:
• How data will be organised in the
database
• How the database will be designed
 The process of designing a relational
database is sometimes called
‘Database Modeling’

17. Design of relational databases
 An excellent example of how this is done
can be found at
http://hsc.csu.edu.au/ipt/info_systems/2-4/da
 Denise Tolhurst steps through the whole
process from the design of the Entity
Relationship Diagram (ERD) through to
the construction of the database tables
 I have used this article with my IPT
classes and used dummy data to create
the database

18. Design of relational databases
 At this website there is also an
interesting and useful article that
describes the development of a
database in terms of the system
development cycle
 This later article has information on
database schema, keys and data
dictionaries

19. Design of relational databases
 Page 30 of the syllabus support document
also has an example of a database
schematic diagram
 Page 31-32 also has a great example of a
relational database that could be used by
a video store
 An interesting exercise is to get the class
to work backward and develop the ERD for
this database, then work forward and
develop the schematic diagram and the
database itself

20. Normalising a database
 Getting a clear and unambiguous
definition of Database Normalisation
is very difficult
 The ultimate goal of normalisation is
simple: to reduce the amount of
redundant data in a database
 How this is done is quite complex
and barely within the ambit of the
syllabus

21. Normalising a database
 Powers => “Normalisation is the process
of organising data into tables so that the
results of using the database are
unambiguous and as intended”
 Ware, Cheleski & Chivers => “Normalising
a relational database involves linking
attributes directly from the original data
fields and eliminating situations where
attributes are linked to other attributes”

22. Normalising a database
 Neither definition is very helpful
 I define Normalisation as: “ the
process of organising data into
groups of tables in order to minimise
data redundancy”
 NOTE: We can never completely
eliminate redundant data

23. Storage and Retrieval

24. Data Independence
 The database and the DBMS are two distinct
entities
 As such each may be stored in separate locations
 For example, the database itself may be stored
on a database server. The software used to
access the database may be Microsoft Access or
FileMaker Pro that is stored on the user’s
computer
 This allows for multiple users to have access the
database simultaneously
 It also means that the DBMS may be updated
without effecting the database

25. Retrieving data from the database
 The most common way of retrieving
information is using Query By Example
 In Access this is done by
• selecting the query button
• selecting the fields you want to search and
display
• Entering a value for a field (criterion)
• Pressing the query button
 This is a highly effective method for doing
a search of data

26. Structured Query Language (SQL)
 SQL is a more powerful method of
retrieving data from a database
 SQL queries are often embedded in
other programming languages e.g.
Cobol
 SQL is a programming language in
itself however, for IPT we only need
to know the basics

27. Structured Query Language (SQL)
 The four basic SQL statements are:
• SELECT - used to display data fields that
satisfy a given rule
• UPDATE- change a value in a field/s
• DELETE - delete a record from a file
• INSERT – add a new record to the file

28. Structured Query Language (SQL)
 SELECT is used to display data fields
that satisfy a given rule
e.g. to search for the phone numbers
and status of all suppliers in Paris we
would use the following
SELECT SupplierPhone, SupplierStatus
FROM tblSupplier.tbl
WHERE SupplierCity = “Paris”;

29. SQL – Wildcards
 These are used when a complete value is
not known
 ! is used to represent a single character
 * is used to represent a group of
characters
e.g. SELECT SupplierName
FROM tblSupplier.tbl
WHERE SupplierCity = “*”;
 This would list all suppliers

30. Joining Tables
 SQL can be used to retrieve data from more than
one table, e.g.
SELECT Surname, City, PartName, Weight
FROM tblSupplier, tblPart
WHERE Supplier.City = “Paris”
 This query displays (selects) the fields Surname
and City from the Supplier table and PartName
and Weight from the Part table, on condition that
the Supplier’s City is Paris

31. Displaying Data
 There are a number of ways to display
data in a database
 We can view the individual data tables,
where we can see all of the records that
make up the table
 We can create forms to view individual
records. We can even select which fields
to display
 We can create a report that will display
the data in a professional manner
 Reports can be made from queries

32. Social and Ethical Issues
 There are many social and ethical issues to
consider with this topic
 The most important are Privacy, Security and
Control and examples may include ‘identity theft’
and the cross-linking of previously independent
government databases
 This has been discussed in earlier lectures
 Also see a provocative source of discussion at
http://www.adcritic.com/interactive/view.php?%20id=
 Most of the existing texts do a good job covering
these and other related issues

33. THE END