8. MANAGING DATA RESOURCES

1
8. MANAGING DATA RESOURCES
8.1
2
LEARNING OBJECTIVES

• COMPARE TRADITIONAL FILE ORGANIZATION
  MANAGEMENT TECHNIQUES
• EXPLAIN PROBLEMS OF TRADITIONAL FILE ENVIRONMENT
• DESCRIBE HOW DATABASE MANAGEMENT SYSTEM
  ORGANIZES DATA

8.2
3
LEARNING OBJECTIVES

• IDENTIFY 3 DATABASE MODELS, PRINCIPLES OF
  DATABASE DESIGN
• DISCUSS DATABASE TRENDS
• ANALYZE MANAGERIAL, ORGANIZATIONAL REQUIREMENTS
  FOR CREATING DATABASE ENVIRONMENT

8.3
4
MANAGEMENT CHALLENGES

• TRADITIONAL DATA FILE ENVIRONMENT
• DATABASE ENVIRONMENT
• DESIGNING DATABASES
• DATABASE TRENDS
• MANAGEMENT REQUIREMENTS FOR DATABASE SYSTEMS

8.4
5
FILE ORGANIZATION

• BIT Binary Digit (0,1Y,NOn, Off)
• BYTE Combination of BITS which represent a
  CHARACTER
• FIELD Collection of BYTES which represent a
  DATUM or Fact
• RECORD Collection of FIELDS which reflect a
  TRANSACTION

8.5
6
FILE ORGANIZATION

• FILE A Collection of Similar RECORDS
• DATABASE An Organizations Electronic Library of
  FILES

8.5
7
FILE ORGANIZATION

• ENTITY Person, Place, Thing, Event about Which
  Data Must be Kept
• ATTRIBUTE Description of a Particular ENTITY
• KEY FIELD Field Used to Retrieve, Update, Sort
  RECORD

8.7
8
KEY FIELD

• Field in Each Record
• Uniquely Identifies THIS Record
• For RETRIEVAL
• UPDATING
• SORTING

8.8
9
SEQUENTIAL VS. DIRECTFILE ORGANIZATION

• SEQUENTIAL Tape Oriented One File Follows
  another Follows Physical Sequence
• DIRECT Disk Oriented Can be Accessed Without
  Regard to Physical Sequence

8.9
10
FILING METHODS

• INDEXED SEQUENTIAL ACCESS METHOD (ISAM)
• EACH RECORD IDENTIFIED BY KEY
• GROUPED IN BLOCKS AND CYLINDERS
• KEYS IN INDEX
• VIRTUAL STORAGE ACCESS METHOD (VSAM)
• MEMORY DIVIDED INTO AREAS INTERVALS
• DYNAMIC FILE SPACE
• VSAM WIDELY USED FOR RELATIONAL DATABASES
• DIRECT FILE ACCESS METHOD

8.10
11
DIRECT FILE ACCESS METHOD

• EACH RECORD HAS KEY FIELD
• KEY FIELD FED INTO TRANSFORM ALGORITHM
• ALGORITHM GENERATES PHYSICAL STORAGE LOCATION OF
  RECORD (RECORD ADDRESS)

8.11
12
TRADITIONAL FILE ENVIRONMENT (FLAT FILE)

• DATA REDUNDANCY
• PROGRAM / DATA DEPENDENCY
• LACK OF FLEXIBILITY
• POOR SECURITY
• LACK OF DATA SHARING AVAILABILITY

8.12
13
DATABASE

• ORGANIZATIONS ELECTRONIC LIBRARY
• STORES MANAGES DATA
• IN A CONVENIENT FORM

8.13
14
DATABASE MANAGEMENT SYSTEM (DBMS)

• SOFTWARE TO CREATE MAINTAIN DATA
• ENABLES BUSINESS APPLICATIONS TO EXTRACT DATA
• INDEPENDENT OF SPECIFIC COMPUTER
  PROGRAMS

DBMS
8.14
15
COMPONENTS OF DBMS

• DATA DEFINITION LANGUAGE
• Defines Data Elements in Database
• DATA MANIPULATION LANGUAGE
• Manipulates Data for Applications
• DATA DICTIONARY
• Formal Definitions of all Variables in Database
  Controls Variety of Database Contents

DBMS
8.15
16
STRUCTURED QUERY LANGUAGE (SQL)

• EMERGING STANDARD
• DATA MANIPULATION LANGUAGE
• FOR RELATIONAL DATABASES

DBMS
8.16
17
TWO VIEWS OF DATA

• PHYSICAL VIEW WHERE IS DATA PHYSICALLY?
• DRIVE, DISK, SURFACE, TRACK, SECTOR (BLOCK),
  RECORD
• TAPE, BLOCK, RECORD NUMBER (KEY)
• LOGICAL VIEW WHAT DATA IS NEEDED BY APPLICATION?
• SUCCESSION OF FACTS NEEDED BY APPLICATION
• NAME, TYPE, LENGTH OF FIELD

DBMS
8.17
BIT BYTE FIELD RECORD FILE DAT
ABASE
18
ADVANTAGES OF DBMS

• REDUCES COMPLEXITY
• REDUCES DATA REDUNDANCY / INCONSISTENCY
• CENTRAL CONTROL OF DATA CREATION / DEFINITIONS
• REDUCES PROGRAM / DATA DEPENDENCE

DBMS
8.18
19
ADVANTAGES OF DBMS

• REDUCES DEVELOPMENT / MAINTENANCE COSTS
• ENHANCES SYSTEM FLEXIBILITY
• INCREASES ACCESS / AVAILABILITY OF INFORMATION

DBMS
8.19
20
HIERARCHICAL DATA MODEL
8.20
21
POINTER

• FIELD IN ONE RECORD IS ADDRESS OF NEXT RECORD IN
  SEQUENCE

8.21
22
TYPES OR RELATIONS
8.22
23
NETWORK DATA MODEL

• VARIATION OF HIERARCHICAL MODEL
• USEFUL FOR MANY-TO-MANY RELATIONSHIPS

8.23
24
RELATIONAL DATA MODEL

• DATA IN TABLE FORMAT
• RELATION TABLE
• TUPLE ROW (RECORD) IN TABLE
• FIELD COLUMN (ATTRIBUTE) IN TABLE

8.24
25
COMPARISON OF DATABASE ALTERNATIVESHIERARCHICAL

• PROCESSING EFFICIENCY HIGH
• FLEXIBILITY LOW
• USER FRIENDLY LOW
• PROGRAM COMPLEXITY HIGH

8.25
26
COMPARISON OF DATABASE ALTERNATIVESNETWORK

• PROCESSING EFFICIENCY MEDIUM / HIGH
• FLEXIBILITY LOW / MEDIUM
• USER FRIENDLY LOW / MODERATE
• PROGRAM COMPLEXITY HIGH

8.26
27
COMPARISON OF DATABASE ALTERNATIVESRELATIONAL

• PROCESSING EFFICIENCY LOW BUT IMPROVING
• FLEXIBILITY HIGH
• USER FRIENDLY HIGH
• PROGRAM COMPLEXITY LOW

8.27
28
CREATING A DATABASE

• CONCEPTUAL DESIGN
• PHYSICAL DESIGN

8.28
29
CREATING A DATABASECONCEPTUAL DESIGN

• ABSTRACT MODEL, BUSINESS PERSPECTIVE
• HOW WILL DATA BE GROUPED?
• RELATIONSHIPS AMONG ELEMENTS
• ESTABLISH END-USER NEEDS

8.29
30
CREATING A DATABASEPHYSICAL DESIGN

• DETAILED MODEL BY DATABASE SPECIALISTS
• ENTITY-RELATIONSHIP DIAGRAM
• NORMALIZATION
• HARDWARE / SOFTWARE SPECIFIC

8.30
31
ENTITY- RELATIONSHIP DIAGRAM
8.31
32
NORMALIZATION

• PROCESS OF CREATING SMALL DATA STRUCTURES FROM
  COMPLEX GROUPS OF DATA
• EXAMPLES
• ACCOUNTS RECEIVABLE
• PERSONNEL RECORDS
• PAYROLL

8.32
33
DATABASE TRENDS

• DISTRIBUTED PROCESSING Multiple Geographical /
  Functional Systems Connected with Network
• DISTRIBUTED DATABASE Data Physically Stored in
  more than one Location
• PARTITIONED
• DUPLICATE

8.33
34
DISTRIBUTED DATABASES

• PARTITIONED remote CPUs (connected to host) have
  files unique to that site, e.g., records on local
  customers
• DUPLICATE each remote CPU has copies of common
  files, e.g., layouts for standard reports
  and forms

8.34
35
DATABASE TRENDS

• OBJECT- ORIENTED Data and Procedures Stored
  Together can be Retrieved, Shared
• HYPERMEDIA Nodes Contain Text, Graphics, Sound,
  Video, Programs. Organizes Data as Nodes.
• MULTIDIMENSIONAL 3D (or higher) Groupings to
  Store Complex Data

8.35
36
DATABASE TRENDS

• DATA WAREHOUSE Organizations Electronic Library
  Stores Consolidated Current Historic Data for
  Management Reporting Analysis
• DATA MART small data warehouse for special
  function, e.g., focused marketing based on
  customer info

8.36
37
COMPONENTS OF DATA WAREHOUSE
8.37
38
DATABASE TRENDS

• ON-LINE ANALYTICAL PROCESSING (OLAP) ability to
  manipulate, analyze large volumes of data from
  multiple perspectives
• LINKING DATABASES TO THE WEB

8.38
39
ELEMENTS OF DATABASE ENVIRONMENT
8.39
40
DATABASE ADMINISTRATION

• DEFINES ORGANIZES DATABASE STRUCTURE AND
  CONTENT
• DEVELOPS SECURITY PROCEDURES
• DEVELOPS DATABASE DOCUMENTATION
• MAINTAINS DBMS

8.40
41
Connect to the INTERNET
PRESS LEFT MOUSE BUTTON ON ICON TO CONNECT TO THE
LAUDON LAUDON WEB SITE FOR MORE INFORMATION ON
THIS CHAPTER
8.41
42
8. MANAGING DATA RESOURCES
8.42