Data Structure & File Systems

Hun Myoung Park, Ph.D.,

Public Management and Policy Analysis ProgramGraduate School of International Relations

International University of Japan

OutlineTraditional Data ApproachDatabase ApproachDatabase Schema

External SchemaConceptual Schema Internal Schema

Relational DatabaseRelations and Primary KeyDatabase Management Systems

2

Information Systems

“A set of interrelated components that collect, manipulate, store, and disseminate data and information.”

Manual information systems Computerized information systems

3

Components of IS 1

Technological components: hardware, software, and telecommunication

Organizational components: data/information, people, rules/procedures

An information system is not simply a set of computer hardware (physical equipment) and software

Telecommunications (Network): connectivity

4

Components of IS 2

Data and information (database) are essential since an information system is all about data and information.

People operate and use the systemsProcedures/rules to use systems and

perform tasks. Formal and informal

5

Basic Functions of IS

Input gathers and captures raw dataProcess converts or transforms data into

useful output (information)Output produces documents or reports of

what was processedFeedback is information from the system

and is used to make changes to input or process in the system

6

Data versus Information

Data: raw factsInformation: facts organized and processed

to have specific meaning and values

7

Type of Data

Text data: letters, numbers, and other characters

Image data: graphic images and picturesAudio data: sounds (music & speech) and

noiseVideo data: moving images and pictures

8

Valuable Information

“To deliver the right information to the right person at the right time” (p.3)

Accurate, relevant, and complete Reliable and verifiable Timely and accessible (the right format) Simple (Well organized)Flexible and secureEconomical (Table 1.2 in p. 7)

9

Five Basic Units 1

Input, output, control, ALU, and memoryInput unit reads data for processingOutput unit displays processed dataControl unit decodes instructions

coordinate flow of data in and out of ALU, register, memory, etc.

10

Five Basic Units 2

ALU (arithmetic and logic unit) processes data

Memory unit : primary (volatile) and secondary (nonvolatile) memory to store data and information

* System unit = Control + ALU+ Memory

11

Specific Information SystemsElectronic government, M-governmentElectronic commerce, M-commerceTransaction processing systems (TPS)Enterprise resource planning (ERP)Management information systems (MIS), PMISDecision support systems (DSS)Knowledge management systems (KMS)Artificial intelligence, expert systems

12

Major Trends in IS 1

Interactivity (Web 2.0) allows users to get an immediate responses

Connectivity connects computers, telephones, and other electronic devices.

13

Major Trends in IS 2Digital convergence means technological

merger of several industries through various devices that exchange information in the digital format used in computers.

“The same information may be exchanged among many kinds of equipment, using the language of computers” (Hutchinson & Sawyer: 2000:1.24)

14

Major Trends in IS 3Software dominates hardwareNetwork based computing (cloud

computing)

15

Why Publicness?

Environmental factorsLegal constraintsPolitical influence Scrutiny Complexity of objectives (ambiguous goals)Fewer incentives for performanceAll these make difference

16

Public Information Systems

More emphasis on openness, accountability, representativeness, equity

More limited by environments (politics)External & vertical linkagesSupport a variety of people without

discrimination (no digital inequality)Incremental approach (Bozeman and

Bretschneider, 1986)

17