Transcript 8. managing data resources

7
7.1
MANAGING
DATA
RESOURCES
Prof Jess Role @ UEAB 2010
LEARNING OBJECTIVES
• COMPARE TRADITIONAL FILE
ORGANIZATION & MANAGEMENT
TECHNIQUES
• DESCRIBE HOW DATABASE
MANAGEMENT SYSTEM
ORGANIZES INFORMATION
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7.2
Prof Jess Role @ UEAB 2010
© 2008 by Prentice Hall
LEARNING OBJECTIVES
• IDENTIFY TYPES OF DATABASE,
PRINCIPLES OF DATABASE DESIGN
• DISCUSS DATABASE TRENDS
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7.3
Prof Jess Role @ UEAB 2010
© 2008 by Prentice Hall
MANAGEMENT CHALLENGES
• TRADITIONAL DATA FILE
ENVIRONMENT
• DATABASE APPROACH TO DATA
MANAGEMENT
• CREATING DATABASE
ENVIRONMENT
• DATABASE TRENDS
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7.4
Prof Jess Role @ UEAB 2010
MANAGEMENT CHALLENGES
1. ORGANIZATIONAL OBSTACLES:
Challenges existing power structure,
requires organizational restructure
2. COST / BENEFIT CONSIDERATIONS:
Large initial costs, delayed benefits,
tangible, intangible
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7.5
Prof Jess Role @ UEAB 2010
FILE ORGANIZATION
• BIT: Binary Digit (0,1; Y,N; On,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
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7.6
Prof Jess Role @ UEAB 2010
FILE ORGANIZATION
• FILE: A Collection of similar
RECORDS
• DATABASE: An Organization’s
Electronic Library of FILES organized
to serve business applications
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7.7
Prof Jess Role @ UEAB 2010
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
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7.8
Prof Jess Role @ UEAB 2010
KEY FIELD
Field in Each Record
Uniquely Identifies THIS Record
For RETRIEVAL
UPDATING
SORTING
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7.9
Prof Jess Role @ UEAB 2010
PROBLEMS WITH TRADITIONAL FILE
ENVIRONMENT
•
•
•
•
•
7.10
DATA REDUNDANCY
PROGRAM / DATA DEPENDENCY
LACK OF FLEXIBILITY
POOR SECURITY
LACK OF DATA
Flat File
SHARING &
AVAILABILITY
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Prof Jess Role @ UEAB 2010
SEQUENTIAL VS. DIRECT
FILE ORGANIZATION
• SEQUENTIAL: Tape oriented; one file
follows another; follows physical
sequence
• DIRECT: Disk oriented; can be
accessed without regard to physical
sequence
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7.11
Prof Jess Role @ UEAB 2010
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
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7.12
Prof Jess Role @ UEAB 2010
DIRECT FILE ACCESS METHOD
• EACH RECORD HAS KEY FIELD
• KEY FIELD FED INTO TRANSFORM
ALGORITHM
• ALGORITHM GENERATES
PHYSICAL STORAGE LOCATION OF
RECORD (RECORD ADDRESS)
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7.13
Prof Jess Role @ UEAB 2010
DATABASE MANAGEMENT SYSTEM (DBMS)
SOFTWARE TO CREATE & MAINTAIN
DATA
ENABLES BUSINESS APPLICATIONS
TO EXTRACT DATA
INDEPENDENT OF SPECIFIC
COMPUTER PROGRAMS
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7.14
DBMS
Prof Jess Role @ UEAB 2010
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, data
elements
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7.15
Prof Jess Role @ UEAB 2010
DBMS
STRUCTURED QUERY LANGUAGE (SQL)
EMERGING STANDARD
DATA MANIPULATION LANGUAGE
FOR RELATIONAL DATABASES
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7.16
DBMS
Prof Jess Role @ UEAB 2010
ELEMENTS OF SQL
• SELECT: List of columns from tables
desired
• FROM: Identifies tables from which
columns will be selected
• WHERE: Includes conditions for
selecting specific rows, conditions
for joining multiple tables
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7.17
DBMS
Prof Jess Role @ UEAB 2010
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
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7.18
Prof Jess Role @ UEAB 2010
DBMS
RELATIONAL DATA MODEL
•
•
•
•
7.19
DATA IN TABLE FORMAT
RELATION: TABLE
TUPLE: ROW (RECORD) IN TABLE
FIELD: COLUMN (ATTRIBUTE) IN TABLE
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HOURS
RATE
TOTAL
ABLE
$ 40.50 $ 10.35 $ 419.18
BAXTER $ 38.00 $ 8.75 $ 332.50
CHEN
$ 42.70 $ 9.25 $ 394.98
DENVER $ 35.90 $ 9.50 $ 341.05
Prof Jess Role @ UEAB 2010
TYPES OR RELATIONS
ONE-TO-ONE:
STUDENT
CLASS
ONE-TO-MANY:
STUDENT
A
MANY-TO-MANY:
Prof Jess Role @ UEAB 2010
STUDENT
B
CLASS
1
STUDENT
A
7.20
ID
STUDENT
C
CLASS
2
STUDENT
B
STUDENT
C
HIERARCHICAL DATA MODEL
ROOT
FIRST
CHILD
2nd
CHILD
7.21
Employer
Compensation
Ratings
Salary
Prof Jess Role @ UEAB 2010
Job
Assignments
Pension
Benefits
Insurance
Health
NETWORK DATA MODEL
• VARIATION OF HIERARCHICAL
MODEL
• USEFUL FOR MANY-TO-MANY
RELATIONSHIPS
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NETWORK
1
NETWORK
A
7.22
Prof Jess Role @ UEAB 2010
NETWORK
2
NETWORK
B
NETWORK
C
OTHER SYSTEMS
• LEGACY SYSTEM: older system
• OBJECT - ORIENTED DBMS: stores
data & procedures as objects
• OBJECT - RELATIONAL DBMS:
hybrid
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7.23
Prof Jess Role @ UEAB 2010
CREATING A DATABASE
• CONCEPTUAL DESIGN
• PHYSICAL DESIGN
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7.24
Prof Jess Role @ UEAB 2010
CREATING A DATABASE
CONCEPTUAL DESIGN:
• ABSTRACT MODEL, BUSINESS
PERSPECTIVE
• HOW WILL DATA BE GROUPED?
• RELATIONSHIPS AMONG
ELEMENTS
• ESTABLISH END-USER
NEEDS
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7.25
Prof Jess Role @ UEAB 2010
CREATING A DATABASE
PHYSICAL DESIGN:
• DETAILED MODEL BY DATABASE
SPECIALISTS
• ENTITY-RELATIONSHIP DIAGRAM
• NORMALIZATION
• HARDWARE / SOFTWARE
SPECIFIC
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7.26
Prof Jess Role @ UEAB 2010
ELEMENTS OF DATABASE
ENVIRONMENT
DATA
DATABASE
TECHNO
LOGY &
MANAGEMENT
ADMINISTRATION
DATABASE
MANAGEMENT
SYSTEM
DATA PLANNING
& MODELING
METHODOLOGY
7.27
Prof Jess Role @ UEAB 2010
USERS
ENTITY- RELATIONSHIP DIAGRAM
ORDER
ORDER: #, DATE, PART #, QUANTITY
1
CAN
HAVE
1
PART: #, DESCRIPTION, UNIT PRICE,
SUPPLIER #
PART
M
CAN
HAVE
1
SUPPLIER
7.28
Prof Jess Role @ UEAB 2010
SUPPLIER: #, NAME,
ADDRESS
NORMALIZATION
PROCESS OF CREATING SMALL
DATA STRUCTURES FROM
COMPLEX GROUPS OF DATA
EXAMPLES:
• ACCOUNTS RECEIVABLE
• PERSONNEL RECORDS
• PAYROLL
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7.29
Prof Jess Role @ UEAB 2010
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
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7.30
Prof Jess Role @ UEAB 2010
DATABASE ADMINISTRATION
• DEFINES & ORGANIZES DATABASE
STRUCTURE AND CONTENT
• DEVELOPS SECURITY PROCEDURES
• DEVELOPS DATABASE
DOCUMENTATION
• MAINTAINS DBMS
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7.31
Prof Jess Role @ UEAB 2010
DATABASE TRENDS
• MULTIDIMENSIONAL DATA ANALYSIS:
3D (or higher) groupings to
store
complex data
• HYPERMEDIA: Nodes contain text,
graphics, sound, video,
programs.
organizes
data as
nodes.
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7.32
Prof Jess Role @ UEAB 2010
DATABASE TRENDS
• DATA WAREHOUSE: Organization’s
electronic library stores consolidated
current & historic data for
management reporting & analysis
• ON-LINE ANALYTICAL PROCESSING
(OLAP): Tools for multidimensional data analysis
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7.33
Prof Jess Role @ UEAB 2010
COMPONENTS OF DATA WAREHOUSE
OPERATIONAL,
HISTORICAL DATA
INTERNAL
DATA
SOURCES
DATA WAREHOUSE
DATA
ACCESS &
ANALYSIS
EXTRACT,
TRANSFORM
INFORMATION
DIRECTORY
EXTERNAL
DATA
SOURCES
7.34
Prof Jess Role @ UEAB 2010
QUERIES &
REPORTS
OLAP
DATA MINING
DATABASE TRENDS
• DATA MART: Small data warehouse
for special function, e.g.,
Focused marketing based
on customer info
• DATAMINING: Tools for finding
hidden patterns, relationships, for predicting trends
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7.35
Prof Jess Role @ UEAB 2010
DATABASE TRENDS
LINKING DATABASES TO THE WEB:
• WEB USER CONNECTS TO VENDOR
DATABASE
• SPECIAL SOFTWARE CONVERTS HTML
TO SQL
• SQL FINDS DATA, SERVER CONVERTS
RESULT TO
HTML
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7.36
Prof Jess Role @ UEAB 2010
MANAGING
DATA
RESOURCES
7.37
Prof Jess Role @ UEAB 2010