UNIT 43 - DATABASE CONCEPTS I

UNIT 43 - DATABASE CONCEPTS I

Compiled with assistance from Gerald White, California State University, Sacramento

  • A. INTRODUCTION
  • B. CONCEPTS IN DATABASE SYSTEMS
  • C. DATABASE MANAGEMENT SYSTEMS
  • D. HIERARCHICAL MODEL
  • E. NETWORK MODEL
  • F. RELATIONAL MODEL
  • REFERENCES
  • EXAM AND DISCUSSION QUESTIONS
  • NOTES

    UNIT 43 - DATABASE CONCEPTS I

    Compiled with assistance from Gerald White, California State University, Sacramento

    A. INTRODUCTION

    Two ways to use DBMS within a GIS

    GIS as a database problem

    B. CONCEPTS IN DATABASE SYSTEMS

    Definition

    Advantages of a database approach

    Views of the database

    C. DATABASE MANAGEMENT SYSTEMS

    Components

    Types of database systems

    D. HIERARCHICAL MODEL

    Summary of features

    Advantages and disadvantages

    E. NETWORK MODEL

    Restrictions

    Summary

    F. RELATIONAL MODEL

    Terminology

    Examples of relations

    unary: COURSES(SUBJECT) binary: PERSONS(NAME,ADDRESS) OWNER(PERSON NAME,HOUSE ADDRESS) ternary: HOUSES(ADDRESS,PRICE,SIZE)

    Keys

    Normalization

    Advantages and disadvantages

    REFERENCES

    Standard database texts:

    Date, G.J., 1987. An Introduction to Database Systems, Addison-Wesley, Reading, MA.

    Howe, D.R., 1983. Data Analysis for Data Base Design, Arnold, London.

    Kent, W., 1983. "A simple guide to five normal forms in relational database theory," Communications of the Association for Computing Machinery 26:120.

    Tsichritzis, D.C. and F.H. Lochovsky, 1977, Database Management Systems, Academic Press, New York.

    The relational model in GIS:

    van Roessel, J.W., 1987. "Design of a spatial data structure using the relational normal forms," International Journal of Geographical Information Systems 1:33-50.

    EXAM AND DISCUSSION QUESTIONS

    1. Compare the four database models (flat file, hierarchical, network and relational) as bases for GIS. What particular features of the relational model account for its popularity?

    2. Polygon overlay has been called a spatial analog of a relational join. Do you agree?

    3. Summarize the arguments against organizing spatial databases as flat files.

    4. Why do you think the term "relation" was chosen for a table of attributes in the relational model?


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