2004 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, by Bodnar/Hopwood 12– 1 Chapter 12 File Processing and Data Management Concepts.

12– 1 2004 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, by Bodnar/Hopwood

Chapter Chapter 1212

File Processing and DataFile Processing and Data

Management ConceptsManagement Concepts

12 – 2 2004 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, by Bodnar/Hopwood

Learning Objective 1Learning Objective 1

Define the basic terms usedDefine the basic terms used

in database technology.in database technology.


Introductory TerminologyIntroductory Terminology

FieldField

Data itemsData items

AttributeAttribute

ElementsElements

These are usedThese are usedinterchangeablyinterchangeably to denote theto denote thesmallest blocksmallest block

of data that willof data that willbe stored andbe stored and

retrieved.retrieved.



A A fieldfield may be a single character or number, or it may be a single character or number, or itmay be composed of many characters or numbers.may be composed of many characters or numbers.

Customer nameCustomer name Employee social security numberEmployee social security number

Purchase order numberPurchase order number Customer account numberCustomer account number



Logical grouping of fields are called Logical grouping of fields are called recordsrecords..

An employeeAn employee A customerA customer

A vendorA vendor An invoiceAn invoice


Data OccurrencesData Occurrences

A record occurrence is a specificA record occurrence is a specificset of data values for the record.set of data values for the record.


Data OccurrencesData Occurrences

For the record EMPLOYEEFor the record EMPLOYEE(NAME,(NAME, NUMBER, AGE)NUMBER, AGE)

we might have the occurrencewe might have the occurrenceEMPLOYEE EMPLOYEE ((Brown, 111222333, 33)Brown, 111222333, 33)


Fixed- and Variable-Length Fixed- and Variable-Length RecordsRecords

In a In a fixed-lengthfixed-length record, both the number record, both the numberof fields and the length (characterof fields and the length (character

size) of each field are fixed.size) of each field are fixed.

In In variable-lengthvariable-length records, the width of the records, the width of thefield can be adjusted to each data occurrence.field can be adjusted to each data occurrence.

A A trailertrailer record is an extension of a master record. record is an extension of a master record.


Several Suppliers andSeveral Suppliers andWarehouses ExampleWarehouses Example

PART_NOPART_NO PNAMEPNAME TYPETYPE COSTCOST

PVEND – the name of the vendor or supplierPVEND – the name of the vendor or supplier

WARHSE – where the part is storedWARHSE – where the part is stored

LOC – the last two digits of the zip codeLOC – the last two digits of the zip code


One Storage Location ExampleOne Storage Location Example

PART (PART_NO, PNAME, TYPE, COST,PART (PART_NO, PNAME, TYPE, COST,PVEND #1, WARHSE #1, LOC#1,PVEND #1, WARHSE #1, LOC#1,PVEND #2, WARHSE #2, LOC#2)PVEND #2, WARHSE #2, LOC#2)


Repeated GroupsRepeated Groups

Repeated groupsRepeated groups are related groups of fields are related groups of fieldsthat repeat themselves in variable-length records.that repeat themselves in variable-length records.

SegmentsSegments GroupsGroups NodesNodes

PART, SUPPLIER, and LOCATIONPART, SUPPLIER, and LOCATIONcan be written as follows:can be written as follows:

PART (PART_NO, PNAME, TYPE, COST)PART (PART_NO, PNAME, TYPE, COST)


Tree Diagram for PART,Tree Diagram for PART,SUPPLIER and LOCATIONSUPPLIER and LOCATION

PARTPART

SUPPLIERSUPPLIER LOCATIONLOCATION


Record Key and File SequenceRecord Key and File Sequence

A A keykey or or record keyrecord key is a data item or is a data item orcombination of data items that uniquelycombination of data items that uniquely

identifies a particular record in a file.identifies a particular record in a file.

Primary sort keyPrimary sort key Secondary sort keySecondary sort key

Tertiary sort keysTertiary sort keys Relative random orderRelative random order



Identify the three levels ofIdentify the three levels of

database architecture.database architecture.


Database Management Database Management Systems and Their ArchitectureSystems and Their Architecture

ConceptualConceptuallevellevel

Database contentsDatabase contentsUses of databaseUses of databaseDesired reportsDesired reportsInformation to be reviewedInformation to be reviewed



LogicalLogicallevellevel

Logical data structures:Logical data structures: Tree (hierarchical)Tree (hierarchical) NetworkNetwork RelationalRelational



PhysicalPhysicallevellevel

Access methods:Access methods: SequentialSequential Indexed-sequentialIndexed-sequential DirectDirect


Conceptual ArchitectureConceptual Architecture

The The Entity-RelationshipEntity-Relationship (E-R) data model (E-R) data modelis a conceptual model for depicting theis a conceptual model for depicting the

relationships between segments in a database.relationships between segments in a database.

AttributeAttribute refers to individual fields or data items. refers to individual fields or data items.


Conceptual ArchitectureConceptual Architecture

The The object-oriented modeling techniqueobject-oriented modeling technique(OMT)(OMT) views the components of the views the components of the

system being modeled as object classes.system being modeled as object classes.

Object classObject class corresponds to a segment. corresponds to a segment.

ObjectObject corresponds to a particular instance. corresponds to a particular instance.


Example of Object-OrientedExample of Object-OrientedData Modeling TechniqueData Modeling Technique

PLANT_EQUIPMENTPLANT_EQUIPMENTACCOUNT_NOACCOUNT_NOCOSTCOSTDEPRECIATIONDEPRECIATION

HEAVY_EQUIPMENTHEAVY_EQUIPMENT MAINTENANCE_FREQMAINTENANCE_FREQ DATE_PURCHASEDDATE_PURCHASED

HAND_TOOLSHAND_TOOLSUSAGEUSAGE



Compare and contrastCompare and contrast

the different logicalthe different logical

models of databases.models of databases.


Logical Data StructuresLogical Data Structures

The relationships that exist betweenThe relationships that exist betweenthe segments in the database arethe segments in the database are

determined by the determined by the logical data structurelogical data structure, , also called the also called the schemaschema or or database modeldatabase model..



What are the three major modelsWhat are the three major modelsof logical data structure?of logical data structure?

1. Tree or hierarchical structures1. Tree or hierarchical structures

2. Network structures2. Network structures

3. Relational models3. Relational models



Tree (hierarchical) modelTree (hierarchical) model(4 levels and 13 nodes)(4 levels and 13 nodes)

AA

BB CC DD EE

FF GG HH II JJ KK

LL MM



AA BB CC

DD FFEE GG HH II

JJ KK

Network modelNetwork model(3 levels and 11 nodes)(3 levels and 11 nodes)



Both trees and networks are implementedBoth trees and networks are implementedwith imbedded with imbedded pointer fieldspointer fields..


Implementing Tree andImplementing Tree andNetwork StructuresNetwork Structures

In a In a list organizationlist organization,, each record each recordcontains one or more pointerscontains one or more pointers(fields) indicating the address(fields) indicating the address

of the next logical recordof the next logical recordwith the same attribute(s).with the same attribute(s).

A A ring structurering structure differs from a list differs from a listin that the last record in the ringin that the last record in the ring

list points back to the first record.list points back to the first record.


Implementing Tree andImplementing Tree andNetwork StructuresNetwork Structures

What is a What is a multiple ring structuremultiple ring structure??

In this type of structure several ringsIn this type of structure several ringspass through individual records.pass through individual records.


List StructureList Structure

RecordsRecords 11 22 33 44 5544 55

22

11RedRed

BlueBlueIndexIndex

Location ofLocation offirst recordfirst record AttributeAttribute

Pointer fieldPointer fieldto next recordto next record

End of listEnd of listindicatorindicator


Ring StructureRing Structure

RecordsRecords 11 22 33 44 5544 55

22

33VaVa

KyKyIndexIndex

Location ofLocation offirst recordfirst record AttributeAttribute

Pointer fieldPointer fieldto next recordto next record

Pointer fieldPointer fieldto first recordto first record

22


Relational Data StructuresRelational Data Structures

What is the What is the relational modelrelational model??

It is a logical data structure thatIt is a logical data structure thatviews the database as a collectionviews the database as a collection

of two-dimensional tables.of two-dimensional tables.

There are no complicated pointers or lists.There are no complicated pointers or lists.





First normal formFirst normal form

Second normal formSecond normal form

Third normal formThird normal form

What are the three normal forms?What are the three normal forms?



Explain the different methodsExplain the different methods

of accessing files.of accessing files.


Database Architecture:Database Architecture:The Physical LevelThe Physical Level

Indexed filesIndexed files

Directly accessed filesDirectly accessed files

Sequentially accessed filesSequentially accessed files


Sequentially Accessed FilesSequentially Accessed Files

Sequential file organization is usefulSequential file organization is usefulwhen batch processing is required.when batch processing is required.

In a In a sequential access filesequential access file, records, recordscan only be accessed incan only be accessed in

their predefined sequence.their predefined sequence.


Indexed FilesIndexed Files

One important type of indexedOne important type of indexedfile is an file is an indexed-sequential fileindexed-sequential file..

An An index fileindex file is one where an attribute has is one where an attribute hasbeen extracted from the records and usedbeen extracted from the records and used

to build a new file whose purpose is toto build a new file whose purpose is toprovide an index to the original file.provide an index to the original file.

Te lne t - sunny

File Disc onnec t Ed it Se tting Network He lp

Te lne t - VAX


Te lne t - sunny


Ping - IBM

File Host Op tions He lp

64 b yte s from p s2 (100.100.100.5 ) :

ic m p _se q = 91 ,

----p s2 PING Sta tistic ----

92 p a c ke ts tra nsm itte d , 92 p a c ke ts re c e ive d ,

0%

ro und -trip (m s) m in/a ug /m a x = 0 /0/20

[< /hom e /zui> ]< /hom e/zui>

64 byte s rec e ived , icm p_64 byte s rec e ived , icm p_



These files are frequentlyThese files are frequentlyreferred to as ISAM files.referred to as ISAM files.

An An indexed-sequential fileindexed-sequential file is a sequential file is a sequential filethat is stored on a DASD and is both indexedthat is stored on a DASD and is both indexed

and physically sorted on the same field.and physically sorted on the same field.

Te lne t - sunny


Te lne t - VAX


Te lne t - sunny


Ping - IBM


64 b yte s from p s2 (100.100.100.5 ) :

ic m p _se q = 91 ,



0%






An ISAM file structurally consistsAn ISAM file structurally consistsof three distinct areas:of three distinct areas:

The indexThe index The prime areaThe prime area The overflow areaThe overflow area

How would a computer locate a fileHow would a computer locate a filerecord whose key is 1002?record whose key is 1002?

Te lne t - sunny


Te lne t - VAX


Te lne t - sunny


Ping - IBM


64 b yte s from p s2 (100.100.100.5 ) :

ic m p _se q = 91 ,



0%





Structure of an ISAM FileStructure of an ISAM File

Master IndexMaster Index

15001500 03000300

Track Index Track Index TrackTrack

addressaddress 03000300

10051005 03010301

Highest keyHighest keyon trackon trackPrime Area Prime Area

1002100203010301

----------------KeyKey DataData

Record foundRecord found

Track index address Track index address Highest keyHighest key

TrackTrackaddressaddress

Track address Track address


Directly Accessed FilesDirectly Accessed Files

Each record is assigned to a storageEach record is assigned to a storagelocation that bears some relationshiplocation that bears some relationship

to the record’s key values.to the record’s key values.

Most direct-access file systems convertMost direct-access file systems converta key to a storage location address.a key to a storage location address.

Direct-accessDirect-access filesfiles allow individual allow individualrecords to be almost instantly retrievedrecords to be almost instantly retrieved

without the use of an index.without the use of an index.


Use of a Direct-Access FileUse of a Direct-Access File

DataDatarecordsrecords

AddAddremainder toremainder todisplacementdisplacementaddress (10)address (10)

FileFilestoragestorage

areaarea

RandomizingRandomizingcomputationcomputation

(÷ 7)(÷ 7)



RemainderRemainderafterafter

divisiondivisionby sevenby seven

DisplacementDisplacementfactorfactor

(initial address(initial addressof file area)of file area)KeyKeyRecordRecord

RecordRecordstoragestorageaddressaddress

11334411

1010101010101010

1515171711112222

11223344

1111131314141111

++ ==

OverflowOverflow



Range ofRange ofrandomizingrandomizingcomputationcomputation

StorageStorageallocated forallocated for

overflowoverflowrecordsrecords

……Record 1 KEY 15Record 1 KEY 15**

……Record 2 KEY 17Record 2 KEY 17Record 3 KEY 11Record 3 KEY 11

…………

Record 4 KEY 22Record 4 KEY 22……

ContentsContentsAddressAddress

1010111112121313141415151616

17171818

OverflowOverflowindicatorindicator


Economic Relations betweenEconomic Relations betweenFile Organization TechniquesFile Organization Techniques

What is the activity ratio?What is the activity ratio?

It is the number of accessed records dividedIt is the number of accessed records dividedby the number of records in the file.by the number of records in the file.

The second economic considerationThe second economic considerationconcerns concerns response timeresponse time..

The basic economics of file processing areThe basic economics of file processing arelargely determined by the largely determined by the activity ratioactivity ratio..


Economic Relations betweenEconomic Relations betweenFile Organization TechniquesFile Organization Techniques

It is the length of time the user must waitIt is the length of time the user must waitfor the system to complete an operation.for the system to complete an operation.

Response time is affectedResponse time is affectedby the physical access time.by the physical access time.

Another factor that can affect response time is howAnother factor that can affect response time is howdata records are physically distributed on the disk.data records are physically distributed on the disk.

What is response time?What is response time?


Learning Objectives 5 and 6Learning Objectives 5 and 6

Explain the benefitsExplain the benefitsof databaseof database

management systems.management systems.

Describe the considerationsDescribe the considerationsthat are appropriate to thethat are appropriate to thedesign of computer-baseddesign of computer-based

files and databases.files and databases.


Database Management Database Management Systems and Databases in Systems and Databases in

PracticePractice

All DBMS contain three common attributesAll DBMS contain three common attributesfor managing and organizing data.for managing and organizing data.

Database Management Systems (DBMS)Database Management Systems (DBMS)are computer programs that enable a user toare computer programs that enable a user tocreate and update files, to select and retrievecreate and update files, to select and retrieve

data, and to generate various outputs and reports.data, and to generate various outputs and reports.


Database Management Database Management Systems and Databases in Systems and Databases in

PracticePractice

Data description language (DDL)Data description language (DDL)

Data manipulation language (DML)Data manipulation language (DML)

Data query language (DQL)Data query language (DQL)

What are these attributes?What are these attributes?


Why Database Management Why Database Management Systems are NeededSystems are Needed

In the absence ofIn the absence of integration, each type ofintegration, each type ofaccounting application such as sales, payroll,accounting application such as sales, payroll,

and receivables will maintain separate,and receivables will maintain separate,independent data files and computer programs.independent data files and computer programs.

DBMS DBMS integrateintegrate, , standardizestandardize, and , and provideprovidesecuritysecurity for various accounting applications. for various accounting applications.


Database Management Database Management ConceptsConcepts

Application OneApplication One

XX YY BBAA

Application TwoApplication Two

XX YY CC DD


Database Management Database Management ConceptsConcepts

XX YY AA BB CC DD

DDAAYYXX

XX YY AA BB

Logical file 1Logical file 1Application oneApplication one

Logical file 2Logical file 2Application twoApplication two

XX YY CC DD

DatabaseDatabasedictionary anddictionary and

access codesaccess codes

DataDatamanipulationmanipulation

routinesroutinesLogical file 3Logical file 3

Security screened inquiry fileSecurity screened inquiry file

DatabaseDatabasesystemsystem


Database DocumentationDatabase Documentationand Administrationand Administration

The data dictionary is simply another file,The data dictionary is simply another file,sort of file of files, whose record occurrencessort of file of files, whose record occurrences

consist of data item descriptions.consist of data item descriptions.

Database dictionariesDatabase dictionaries are used both alone are used both aloneand with DBMS to centralize, document,and with DBMS to centralize, document,

control, and coordinate the use of datacontrol, and coordinate the use of datawithin an organization.within an organization.


Data Dictionary FormatData Dictionary Format

SpecificationsSpecifications NameName DefinitionDefinition AliasesAliases

CharacteristicsCharacteristics SizeSize Range of valuesRange of values EncodingEncoding Editing dataEditing data

UtilizationUtilization OwnerOwner Where usedWhere used Security codeSecurity code Last updateLast update

12– 55 2004 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, by Bodnar/Hopwood

End of Chapter End of Chapter 1212

2004 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, by Bodnar/Hopwood 12– 1 Chapter 12 File Processing and Data Management Concepts.

Documents

accounting information

database management

cost slide

invoice slide

supplierlocation slide

zip code slide

data occurrences

record key