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Transcript of 7.1 © 2002 by Prentice Hall c h a p t e r 7 7 MANAGING DATA DATARESOURCES.
7.7.11 © 2002 by Prentice Hall
c h a p t e r
77MANAGINGMANAGING
DATA DATA
RESOURCESRESOURCES
7.7.22 © 2002 by Prentice Hall
LEARNING OBJECTIVESLEARNING OBJECTIVES
• COMPARE TRADITIONAL FILE COMPARE TRADITIONAL FILE ORGANIZATION & MANAGEMENT ORGANIZATION & MANAGEMENT TECHNIQUESTECHNIQUES
• DESCRIBE HOW DATABASE DESCRIBE HOW DATABASE MANAGEMENT SYSTEM MANAGEMENT SYSTEM ORGANIZES ORGANIZES INFORMATIONINFORMATION
**
© 2002 by Prentice Hall
7.7.33 © 2002 by Prentice Hall
LEARNING OBJECTIVESLEARNING OBJECTIVES
• IDENTIFY TYPES OF DATABASE, IDENTIFY TYPES OF DATABASE, PRINCIPLES OF DATABASE DESIGNPRINCIPLES OF DATABASE DESIGN
• DISCUSS DATABASE TRENDSDISCUSS DATABASE TRENDS
**
© 2002 by Prentice Hall
7.7.44 © 2002 by Prentice Hall
MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES
• TRADITIONAL DATA FILE TRADITIONAL DATA FILE ENVIRONMENTENVIRONMENT
• DATABASE APPROACH TO DATA DATABASE APPROACH TO DATA MANAGEMENTMANAGEMENT
• CREATING DATABASE CREATING DATABASE ENVIRONMENTENVIRONMENT
• DATABASE TRENDSDATABASE TRENDS
**
7.7.55 © 2002 by Prentice Hall
MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES
1. ORGANIZATIONAL OBSTACLES:1. ORGANIZATIONAL OBSTACLES: Challenges existing power structure, Challenges existing power structure, requires organizational restructurerequires organizational restructure
2. COST / BENEFIT CONSIDERATIONS:2. COST / BENEFIT CONSIDERATIONS: Large initial costs, delayed benefits, Large initial costs, delayed benefits, tangible, intangibletangible, intangible
**
7.7.66 © 2002 by Prentice Hall
FILE ORGANIZATIONFILE ORGANIZATION
• BIT:BIT: Binary Digit (0,1; Y,N; On,Off)Binary Digit (0,1; Y,N; On,Off)
• BYTE:BYTE: Combination of BITS which Combination of BITS which represent a CHARACTERrepresent a CHARACTER
• FIELD:FIELD: Collection of BYTES which Collection of BYTES which represent a DATUM or Factrepresent a DATUM or Fact
• RECORD:RECORD: Collection of FIELDS which Collection of FIELDS which reflect a TRANSACTIONreflect a TRANSACTION
**
7.7.77 © 2002 by Prentice Hall
FILE ORGANIZATIONFILE ORGANIZATION
• FILE:FILE: A Collection of similar A Collection of similar RECORDSRECORDS
• DATABASE:DATABASE: An Organization’s An Organization’s Electronic Library of FILES Electronic Library of FILES organized to serve business organized to serve business applicationsapplications
**
7.7.88 © 2002 by Prentice Hall
FILE ORGANIZATIONFILE ORGANIZATION
• ENTITY:ENTITY: Person, place, thing, event Person, place, thing, event about which data must be keptabout which data must be kept
• ATTRIBUTE:ATTRIBUTE: Description of a Description of a particular ENTITYparticular ENTITY
• KEY FIELD:KEY FIELD: Field used to retrieve, Field used to retrieve, update, sort RECORDupdate, sort RECORD
**
7.7.99 © 2002 by Prentice Hall
KEY FIELDKEY FIELD
Field in Each RecordField in Each Record
Uniquely Identifies Uniquely Identifies THISTHIS Record Record
For RETRIEVALFor RETRIEVAL
UPDATINGUPDATING
SORTINGSORTING
**
7.7.1010 © 2002 by Prentice Hall
• DATA REDUNDANCYDATA REDUNDANCY• PROGRAM / DATA DEPENDENCYPROGRAM / DATA DEPENDENCY• LACK OF FLEXIBILITYLACK OF FLEXIBILITY• POOR SECURITYPOOR SECURITY• LACK OF DATA LACK OF DATA SHARING SHARING
& & AVAILABILITYAVAILABILITY
**
PROBLEMS WITH TRADITIONAL FILE PROBLEMS WITH TRADITIONAL FILE ENVIRONMENTENVIRONMENT
Flat FileFlat File
7.7.1111 © 2002 by Prentice Hall
SEQUENTIAL VS. DIRECTSEQUENTIAL VS. DIRECTFILE ORGANIZATIONFILE ORGANIZATION
• SEQUENTIAL:SEQUENTIAL: Tape oriented; one file Tape oriented; one file follows another; follows physical follows another; follows physical sequencesequence
• DIRECT:DIRECT: Disk oriented; can be Disk oriented; can be accessed without regard to physical accessed without regard to physical sequencesequence
**
7.7.1212 © 2002 by Prentice Hall
FILING METHODSFILING METHODS
• INDEXED SEQUENTIAL ACCESS METHODINDEXED SEQUENTIAL ACCESS METHOD (ISAM) :(ISAM) :– EACH RECORD IDENTIFIED BY KEYEACH RECORD IDENTIFIED BY KEY
– GROUPED IN BLOCKS AND CYLINDERSGROUPED IN BLOCKS AND CYLINDERS
– KEYS IN INDEXKEYS IN INDEX
• VIRTUAL STORAGE ACCESS METHODVIRTUAL STORAGE ACCESS METHOD (VSAM) :(VSAM) :– MEMORY DIVIDED INTO AREAS & INTERVALSMEMORY DIVIDED INTO AREAS & INTERVALS
– DYNAMIC FILE SPACE DYNAMIC FILE SPACE
VSAM WIDELY USED FOR RELATIONAL VSAM WIDELY USED FOR RELATIONAL DATABASESDATABASES
• DIRECT FILE ACCESS METHODDIRECT FILE ACCESS METHOD
**
7.7.1313 © 2002 by Prentice Hall
DIRECT FILE ACCESS METHODDIRECT FILE ACCESS METHOD
• EACH RECORD HAS KEY FIELDEACH RECORD HAS KEY FIELD
• KEY FIELD FED INTO TRANSFORM KEY FIELD FED INTO TRANSFORM ALGORITHMALGORITHM
• ALGORITHM GENERATES ALGORITHM GENERATES PHYSICAL STORAGE LOCATION OF PHYSICAL STORAGE LOCATION OF RECORD (RECORD ADDRESS)RECORD (RECORD ADDRESS)
**
7.7.1414 © 2002 by Prentice Hall
DATABASE MANAGEMENT SYSTEM (DBMS)DATABASE MANAGEMENT SYSTEM (DBMS)
SOFTWARE TO CREATE & MAINTAIN SOFTWARE TO CREATE & MAINTAIN DATA DATA
ENABLES BUSINESS APPLICATIONS ENABLES BUSINESS APPLICATIONS TO EXTRACT DATA TO EXTRACT DATA
INDEPENDENT OF SPECIFIC INDEPENDENT OF SPECIFIC COMPUTER PROGRAMS COMPUTER PROGRAMS
**
DBMS
7.7.1515 © 2002 by Prentice Hall
COMPONENTS OF DBMS:COMPONENTS OF DBMS:
• DATA DEFINITION LANGUAGE:DATA DEFINITION LANGUAGE:– Defines data elements in databaseDefines data elements in database
• DATA MANIPULATION LANGUAGE:DATA MANIPULATION LANGUAGE:– Manipulates data for applicationsManipulates data for applications
• DATA DICTIONARY:DATA DICTIONARY:– Formal definitions of all variables in Formal definitions of all variables in
database, controls variety of database database, controls variety of database contents, data elementscontents, data elements
** DBMS
7.7.1616 © 2002 by Prentice Hall
STRUCTURED QUERY LANGUAGE (SQL)STRUCTURED QUERY LANGUAGE (SQL)
EMERGING STANDARD EMERGING STANDARD
DATA MANIPULATION LANGUAGEDATA MANIPULATION LANGUAGE
FOR RELATIONAL DATABASESFOR RELATIONAL DATABASES
**
DBMS
7.7.1717 © 2002 by Prentice Hall
ELEMENTS OF SQLELEMENTS OF SQL
• SELECT:SELECT: List of columns from tables List of columns from tables desireddesired
• FROM:FROM: Identifies tables from which Identifies tables from which columns will be selectedcolumns will be selected
• WHERE:WHERE: Includes conditions for Includes conditions for selecting specific rows, conditions for selecting specific rows, conditions for joining multiple tablesjoining multiple tables
**DBM
S
7.7.1818 © 2002 by Prentice Hall
TWO VIEWS OF DATATWO VIEWS OF DATA
BIT
BYTE
FIELD
RECORD
FILE
DATABASE
• PHYSICAL VIEW:PHYSICAL VIEW: Where is data physically?Where is data physically?
– DRIVE, DISK, SURFACE, TRACK, SECTOR DRIVE, DISK, SURFACE, TRACK, SECTOR (BLOCK), RECORD(BLOCK), RECORD
– TAPE, BLOCK, RECORD NUMBER (KEY)TAPE, BLOCK, RECORD NUMBER (KEY)
• LOGICAL VIEW:LOGICAL VIEW: What data is needed by What data is needed by application?application?
– SUCCESSION OF FACTS NEEDED BY SUCCESSION OF FACTS NEEDED BY APPLICATIONAPPLICATION
– NAME, TYPE, LENGTH OF FIELDNAME, TYPE, LENGTH OF FIELD
**DBM
S
7.7.1919 © 2002 by Prentice Hall
RELATIONAL DATA MODELRELATIONAL DATA MODEL
• DATA IN TABLE FORMATDATA IN TABLE FORMAT
• RELATION: TABLERELATION: TABLE
• TUPLE: ROW (RECORD) IN TABLETUPLE: ROW (RECORD) IN TABLE
• FIELD: COLUMN (ATTRIBUTE) IN TABLEFIELD: COLUMN (ATTRIBUTE) IN TABLE
**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$
7.7.2020 © 2002 by Prentice Hall
TYPES OR RELATIONSTYPES OR RELATIONS
ONE-TO-ONE:ONE-TO-ONE: STUDENT ID
ONE-TO-MANY:ONE-TO-MANY:CLASS
STUDENTA
STUDENTB
STUDENTC
MANY-TO-MANY:MANY-TO-MANY:
STUDENTA
STUDENTB
STUDENTC
CLASS1
CLASS2
7.7.2121 © 2002 by Prentice Hall
ROOT
FIRST CHILD
2nd CHILD
RatingsRatings SalarySalary
CompensationCompensation JobJobAssignmentsAssignments
PensionPension InsuranceInsurance HealthHealth
BenefitsBenefits
EmployerEmployer
HIERARCHICAL DATA MODELHIERARCHICAL DATA MODEL
7.7.2222 © 2002 by Prentice Hall
NETWORK DATA MODELNETWORK DATA MODEL
• VARIATION OF HIERARCHICAL VARIATION OF HIERARCHICAL MODELMODEL
• USEFUL FOR MANY-TO-MANY USEFUL FOR MANY-TO-MANY RELATIONSHIPSRELATIONSHIPS
**
NETWORKA
NETWORKB
NETWORKC
NETWORK1
NETWORK2
7.7.2323 © 2002 by Prentice Hall
OTHER SYSTEMSOTHER SYSTEMS
• LEGACY SYSTEM:LEGACY SYSTEM: older system older system
• OBJECT - ORIENTED DBMS:OBJECT - ORIENTED DBMS: stores stores data & procedures as objectsdata & procedures as objects
• OBJECT - RELATIONAL DBMS:OBJECT - RELATIONAL DBMS: hybridhybrid
**
7.7.2424 © 2002 by Prentice Hall
CREATING A DATABASECREATING A DATABASE
• CONCEPTUAL DESIGNCONCEPTUAL DESIGN
• PHYSICAL DESIGNPHYSICAL DESIGN
**
7.7.2525 © 2002 by Prentice Hall
CREATING A DATABASECREATING A DATABASECONCEPTUAL DESIGN:CONCEPTUAL DESIGN:
• ABSTRACT MODEL, BUSINESS ABSTRACT MODEL, BUSINESS PERSPECTIVEPERSPECTIVE
• HOW WILL DATA BE GROUPED?HOW WILL DATA BE GROUPED?
• RELATIONSHIPS AMONG ELEMENTSRELATIONSHIPS AMONG ELEMENTS
• ESTABLISH END-USER ESTABLISH END-USER NEEDSNEEDS
**
7.7.2626 © 2002 by Prentice Hall
• DETAILED MODEL BY DATABASE DETAILED MODEL BY DATABASE SPECIALISTS SPECIALISTS
• ENTITY-RELATIONSHIP DIAGRAMENTITY-RELATIONSHIP DIAGRAM
• NORMALIZATIONNORMALIZATION
• HARDWARE / SOFTWAREHARDWARE / SOFTWARESPECIFICSPECIFIC
**
CREATING A DATABASECREATING A DATABASEPHYSICAL DESIGN:PHYSICAL DESIGN:
7.7.2727 © 2002 by Prentice Hall
ELEMENTS OF DATABASE ELEMENTS OF DATABASE ENVIRONMENTENVIRONMENT
DATABASE MANAGEMENT
SYSTEM
DATA
ADMINISTRATION DATABASETECHNOLOGY & MANAGEMENT
USERS
DATA PLANNING & MODELING
METHODOLOGY
7.7.2828 © 2002 by Prentice Hall
ENTITY- RELATIONSHIP DIAGRAMENTITY- RELATIONSHIP DIAGRAM
1
1
M
1
ORDER
CAN HAVE
PART
SUPPLIER
CAN HAVE
ORDER: #, DATE, PART #, QUANTITY
PART: #, DESCRIPTION, UNIT PRICE, SUPPLIER #
SUPPLIER: #, NAME, ADDRESS
7.7.2929 © 2002 by Prentice Hall
NORMALIZATIONNORMALIZATION
PROCESS OF CREATING SMALL DATA PROCESS OF CREATING SMALL DATA STRUCTURES FROM COMPLEX STRUCTURES FROM COMPLEX GROUPS OF DATAGROUPS OF DATA
EXAMPLES:EXAMPLES:
• ACCOUNTS RECEIVABLEACCOUNTS RECEIVABLE
• PERSONNEL RECORDSPERSONNEL RECORDS
• PAYROLLPAYROLL
**
7.7.3030 © 2002 by Prentice Hall
DISTRIBUTEDDISTRIBUTED DATABASESDATABASES
• PARTITIONED:PARTITIONED: remote CPUs (connected remote CPUs (connected to host) have files unique to that site, to host) have files unique to that site, e.g., records on local customerse.g., records on local customers
• DUPLICATE:DUPLICATE: each remote CPU has each remote CPU has copies of common files, copies of common files, e.g., layouts for standard e.g., layouts for standard reports reports and formsand forms
**
7.7.3131 © 2002 by Prentice Hall
DATABASE ADMINISTRATIONDATABASE ADMINISTRATION
• DEFINES & ORGANIZES DATABASE DEFINES & ORGANIZES DATABASE STRUCTURE AND CONTENTSTRUCTURE AND CONTENT
• DEVELOPS SECURITY PROCEDURESDEVELOPS SECURITY PROCEDURES• DEVELOPS DATABASE DOCUMENTATIONDEVELOPS DATABASE DOCUMENTATION• MAINTAINS DBMSMAINTAINS DBMS
**
7.7.3232 © 2002 by Prentice Hall
DATABASE TRENDSDATABASE TRENDS
• MULTIDIMENSIONAL DATA ANALYSIS:MULTIDIMENSIONAL DATA ANALYSIS: 3D (or higher) groupings to 3D (or higher) groupings to store store complex datacomplex data
• HYPERMEDIA:HYPERMEDIA: Nodes contain text, Nodes contain text, graphics, sound, video, graphics, sound, video, programs. organizes programs. organizes data as nodes.data as nodes.
**
7.7.3333 © 2002 by Prentice Hall
DATABASE TRENDSDATABASE TRENDS
• DATA WAREHOUSE:DATA WAREHOUSE: Organization’s Organization’s electronic library stores consolidated electronic library stores consolidated current & historic data for current & historic data for management reporting & analysismanagement reporting & analysis
• ON-LINE ANALYTICAL PROCESSING ON-LINE ANALYTICAL PROCESSING (OLAP):(OLAP): Tools for multi-Tools for multi-dimensional data analysisdimensional data analysis
**
7.7.3434 © 2002 by Prentice Hall
COMPONENTS OF DATA WAREHOUSECOMPONENTS OF DATA WAREHOUSE
INFORMATIONDIRECTORY
INTERNALDATASOURCES
EXTERNALDATASOURCES
OPERATIONAL,HISTORICAL DATA
DATA WAREHOUSE
EXTRACT,TRANSFORM
DATAACCESS &ANALYSIS
QUERIES &REPORTS
OLAP
DATA MINING
7.7.3535 © 2002 by Prentice Hall
DATABASE TRENDSDATABASE TRENDS
• DATA MART:DATA MART: Small data warehouse Small data warehouse for special function, e.g., for special function, e.g., Focused marketing based Focused marketing based
on customer infoon customer info
• DATAMINING:DATAMINING: Tools for finding Tools for finding hidden patterns, relation-hidden patterns, relation-
ships, for predicting trendsships, for predicting trends
**
7.7.3636 © 2002 by Prentice Hall
DATABASE TRENDSDATABASE TRENDS
LINKING DATABASES TO THE WEB:LINKING DATABASES TO THE WEB:
• WEB USER CONNECTS TO VENDOR WEB USER CONNECTS TO VENDOR DATABASEDATABASE
• SPECIAL SOFTWARE CONVERTS SPECIAL SOFTWARE CONVERTS HTML TO SQLHTML TO SQL
• SQL FINDS DATA, SERVER CONVERTS SQL FINDS DATA, SERVER CONVERTS RESULT TO RESULT TO HTMLHTML
**
7.7.3737 © 2002 by Prentice Hall
c h a p t e r
77MANAGINGMANAGING
DATA DATA
RESOURCESRESOURCES