Transcript
6.6.11
CHAPTER 6. MANAGING CHAPTER 6. MANAGING DATA RESOURCESDATA RESOURCES
6.6.22
LEARNING OBJECTIVESLEARNING OBJECTIVES
• COMPARE TRADITIONAL FILE COMPARE TRADITIONAL FILE ORGANIZATION & MANAGEMENT ORGANIZATION & MANAGEMENT TECHNIQUESTECHNIQUES
• EXPLAIN PROBLEMS OF TRADITIONAL EXPLAIN PROBLEMS OF TRADITIONAL FILE ENVIRONMENTFILE ENVIRONMENT
• DESCRIBE HOW DATABASE DESCRIBE HOW DATABASE MANAGEMENT SYSTEM MANAGEMENT SYSTEM ORGANIZES ORGANIZES INFORMATIONINFORMATION
**
6.6.33
LEARNING OBJECTIVESLEARNING OBJECTIVES
• IDENTIFY TYPES OF DATABASE, IDENTIFY TYPES OF DATABASE, PRINCIPLES OF DATABASE DESIGNPRINCIPLES OF DATABASE DESIGN
• DISCUSS DATABASE TRENDSDISCUSS DATABASE TRENDS• ANALYZE MANAGERIAL, ANALYZE MANAGERIAL,
ORGANIZATIONAL REQUIREMENTS FOR ORGANIZATIONAL REQUIREMENTS FOR CREATING DATABASE CREATING DATABASE ENVIRONMENTENVIRONMENT
**
6.6.44
MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES
• TRADITIONAL DATA FILE TRADITIONAL DATA FILE ENVIRONMENTENVIRONMENT
• DATABASE ENVIRONMENTDATABASE ENVIRONMENT
• DESIGNING DATABASESDESIGNING DATABASES
• DATABASE TRENDSDATABASE TRENDS
• MANAGEMENT REQUIREMENTS FOR MANAGEMENT REQUIREMENTS FOR DATABASE SYSTEMSDATABASE SYSTEMS
**
6.6.55
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
**
6.6.66
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 FILESElectronic Library of FILES
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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
**
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KEY FIELDKEY FIELD
Field in Each RecordField in Each Record
Uniquely Identifies THIS RecordUniquely Identifies THIS Record
For For RETRIEVALRETRIEVAL
UPDATINGUPDATING
SORTINGSORTING
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SEQUENTIAL VS. DIRECTSEQUENTIAL VS. DIRECTFILE ORGANIZATIONFILE ORGANIZATION
• SEQUENTIAL:SEQUENTIAL: Tape Oriented; One Tape Oriented; One File Follows Another; Follows File Follows Another; Follows Physical SequencePhysical Sequence
• DIRECT:DIRECT: Disk Oriented; Can be Disk Oriented; Can be Accessed Without Regard to Accessed Without Regard to Physical SequencePhysical Sequence
**
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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
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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)
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• 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
**
TRADITIONAL FILE TRADITIONAL FILE ENVIRONMENT (FLAT FILE)ENVIRONMENT (FLAT FILE)
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DATABASEDATABASE
ORGANIZATION’S ELECTRONIC ORGANIZATION’S ELECTRONIC LIBRARYLIBRARY
STORES & MANAGES DATASTORES & MANAGES DATA
IN A CONVENIENT FORMIN A CONVENIENT FORM
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DATABASE MANAGEMENT DATABASE MANAGEMENT SYSTEM (DBMS)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
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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 contentscontents
**DBM
S
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STRUCTURED QUERY STRUCTURED QUERY LANGUAGE (SQL)LANGUAGE (SQL)
EMERGING STANDARD EMERGING STANDARD
DATA MANIPULATION LANGUAGEDATA MANIPULATION LANGUAGE
FOR RELATIONAL DATABASESFOR RELATIONAL DATABASES
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DBMS
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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
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RELATIONAL DATA MODELRELATIONAL DATA MODEL
• DATA IN TABLE FORMATDATA IN TABLE FORMAT
• RELATION:RELATION: TABLE TABLE
• TUPLE:TUPLE: ROW (RECORD) IN TABLE ROW (RECORD) IN TABLE
• FIELD:FIELD: COLUMN (ATTRIBUTE) IN TABLE 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$
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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
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ROOT
FIRST CHILD
2nd CHILD
RatingsRatings SalarySalary
CompensationCompensation JobJobAssignmentsAssignments
PensionPension InsuranceInsurance HealthHealth
BenefitsBenefits
EmployerEmployer
HIERARCHICAL DATA MODELHIERARCHICAL DATA MODEL
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NETWORK DATA MODELNETWORK DATA MODEL
• VARIATION OF HIERARCHICAL VARIATION OF HIERARCHICAL MODELMODEL
• USEFUL FOR MANY-TO-MANY USEFUL FOR MANY-TO-MANY RELATIONSHIPSRELATIONSHIPS
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NETWORKA
NETWORKB
NETWORKC
NETWORK1
NETWORK2
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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: hybrid hybrid
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CREATING A DATABASECREATING A DATABASE
• CONCEPTUAL DESIGNCONCEPTUAL DESIGN
• PHYSICAL DESIGNPHYSICAL DESIGN
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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
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CREATING A DATABASECREATING A DATABASEPHYSICAL DESIGN:PHYSICAL DESIGN:• DETAILED MODEL BY DATABASE DETAILED MODEL BY DATABASE
SPECIALISTS SPECIALISTS
• ENTITY-RELATIONSHIP DIAGRAMENTITY-RELATIONSHIP DIAGRAM
• NORMALIZATIONNORMALIZATION
• HARDWARE / HARDWARE / SOFTWARESOFTWARE SPECIFICSPECIFIC
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ENTITY- RELATIONSHIP ENTITY- RELATIONSHIP DIAGRAMDIAGRAM
1
1
M
1
ORDER
CAN HAVE
PART
SUPPLIER
CAN HAVE
ORDER: #, DATE, PART #, QUANTITY
PART: #, DESCRIPTION, UNIT PRICE, SUPPLIER #
SUPPLIER: #, NAME, ADDRESS
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NORMALIZATIONNORMALIZATIONPROCESS 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
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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
**
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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.
**
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DATABASE TRENDSDATABASE TRENDS• DATA WAREHOUSE:DATA WAREHOUSE: Organization’s Organization’s
electronic library stores consolidated electronic library stores consolidated current & historic data for management current & historic data for management reporting & analysisreporting & analysis
• DATA MART:DATA MART: Small data warehouse for Small data warehouse for special function, e.G., special function, e.G., Focused Focused marketing based marketing based on customer on customer infoinfo
**
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COMPONENTS OF DATA WAREHOUSECOMPONENTS OF DATA WAREHOUSE
INFORMATIONDIRECTORY
INTERNALDATASOURCES
EXTERNALDATASOURCES
OPERATIONAL,HISTORICAL DATA
DATA WAREHOUSE
EXTRACT,TRANSFORM
DATAACCESS &ANALYSIS
QUERIES &REPORTS
OLAP
DATA MINING
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DATABASE TRENDSDATABASE TRENDS
• ON-LINE ANALYTICAL PROCESSING ON-LINE ANALYTICAL PROCESSING (OLAP):(OLAP): ability to manipulate, ability to manipulate, analyze large volumes of data from analyze large volumes of data from multiple perspectivesmultiple perspectives
• LINKING DATABASES TO THE WEBLINKING DATABASES TO THE WEB
**
6.6.3333
ELEMENTS OF DATABASE ELEMENTS OF DATABASE ENVIRONMENTENVIRONMENT
DATABASE MANAGEMENT
SYSTEM
DATA
ADMINISTRATION DATABASETECHNOLOGY & MANAGEMENT
USERS
DATA PLANNING & MODELING
METHODOLOGY
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DATABASE DATABASE ADMINISTRATIONADMINISTRATION
• DEFINES & ORGANIZES DATABASE DEFINES & ORGANIZES DATABASE STRUCTURE AND CONTENTSTRUCTURE AND CONTENT
• DEVELOPS SECURITY PROCEDURESDEVELOPS SECURITY PROCEDURES• DEVELOPS DATABASE DOCUMENTATIONDEVELOPS DATABASE DOCUMENTATION• MAINTAINS DBMSMAINTAINS DBMS
**
6.6.3535
Connect to the INTERNETConnect to the INTERNET
Laudon/Laudon Web site: http://www.prenhall.com/laudon
Additional Internet Resources related to this chapter:http://www.oracle.comnews:comp.databasesnews:comp.databases.theoryhttp://w3.one.net/~jhoffman/sqltut.htm
http://www.compapp.dcu.ie/databases/welcome.htmlhttp://www.acm.org/sigmodhttp://www.dwinfocenter.org/http://138.87.1.4/DataWarehouse/whselead.html
© 2001 Laudon & Laudon, Essentials of Management Information Systems 4/e
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CHAPTER 6. MANAGING CHAPTER 6. MANAGING DATA RESOURCESDATA RESOURCES
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