Data Structure & File Systems Hun Myoung Park, Ph.D., Public Management and Policy Analysis Program Graduate School of International Relations International University of Japan

Outline  Traditional Data Approach  Database Approach  Database Schema  External Schema  Conceptual Schema  Internal Schema  Relational Database  Relations and Primary Key  Database 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 systems  Procedures/rules to use systems and perform tasks. Formal and informal 5

Basic Functions of IS  Input gathers and captures raw data  Process converts or transforms data into useful output (information)  Output produces documents or reports of what was processed  Feedback is information from the system and is used to make changes to input or process in the system 6

Data versus Information  Data: raw facts  Information: 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 pictures  Audio data: sounds (music & speech) and noise  Video 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 secure  Economical (Table 1.2 in p. 7) 9

Five Basic Units 1  Input, output, control, ALU, and memory  Input unit reads data for processing  Output unit displays processed data  Control 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 Systems  Electronic government, M- government  Electronic commerce, M- commerce  Transaction processing systems (TPS)  Enterprise resource planning (ERP)  Management information systems (MIS), PMIS  Decision 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 2  Digital 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 3  Software dominates hardware  Network based computing (cloud computing) 15

Why Publicness?  Environmental factors  Legal constraints  Political influence  Scrutiny  Complexity of objectives (ambiguous goals)  Fewer incentives for performance  All these make difference 16

Public Information Systems  More emphasis on openness, accountability, representativeness, equity  More limited by environments (politics)  External & vertical linkages  Support a variety of people without discrimination (no digital inequality)  Incremental approach (Bozeman and Bretschneider, 1986) 17