Databases ?2014, Fall

Pusan National UniversityKi-Joune Li

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Questions

• Q1 – Describe actual political situation in Korea.• Q2 – Make it machine-understandable.

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Overview on Databases

Computer World

Real World

phase 1 phase 2

understanding modeling

implementation design and coding

Application Management

phase 3

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Comparison with Software Lifecycle

Requirement Analysis

Functional Specification

Design

Development Environments

Coding

Test

Maintenance

Software Life Cycle – Waterfall Model

Requirement Analysis

Modeling

Schema Design

DB Environments

Data Collection and Input

Quality Control

Management and Retrieval

DB Life Cycle

part I

part II

part III

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Plan

• Part I – Data Modelingo Understanding it in formal wayso Object-Oriented Data Model (UML Class Diagram)o Relational Data Model (E-R Model)

• Part II – Database Designo Relational Database Schema Design

• Part III – Query Languageo SQL

• Part IV – Semi-Structured Data Modelo XML

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Two different aspects of DB

Logical (or Conceptual) Representation

Physical RepresentationHow to physically organize

data in file systems DBMS Issue

How to conceptually understand and describe

information Database IssueIndependence

Applications are developedon the conceptual understanding

of real worldApplications

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Three Level Schema of Databases

Logical (or Conceptual) Representation

Physical Representation

Independence

Applications

Physical level (schema)

Conceptual level (schema)

External level (schema)

File Processing in Spring Semester