Introduction to Database Management Systems: Structure, Applications, and Key Benefits

Explore the essentials of Database Management Systems (DBMS), including fundamental concepts, key applications in various industries, and advantages like data integrity, security, and independence. This presentation delves into data models such as hierarchical, network, relational, and object-oriented models, with practical examples and a deep dive into the structure and functions of tables, records, fields, and keys.

1. DATABASE MANAGEMENT SYSTEM

2. INTRODUCTION TO DATABASES
Adatabaseisacollectionofdataorganizedtoservemany
application.Byusingcentralizeddataitcaneasilybeaccessed,
managed,andupdated.
AndaDATABASEMANAGEMENTSYSTEM(DBMS)isacollection
ofprogramsthatenablesyoutostore,modify,andextract
informationfromadatabase.

3. ADVANTAGES OF USING A DATABASE APPROACH
•FlexibleDataAccess.
•ImprovedDataIntegrity(purity,).
•ImprovedDataSecurity.
•DataIndependence.
•ReducedDataRedundancy(excess).
•AbilitytoShareandRelateData
•StandardisationofData.
•IncreasedProductivity.

5. DBMS and Its Applications:
ADATABASEMANAGEMENT SYSTEM(DBMS)isa
computerizedrecord-keepingsystem.Itisarepositoryora
containerforcollectionofcomputerizeddatafiles.
Applicationareasfollows:
–Banking
–Airlines
–Universities
–Manufacturingandselling
–Humanresources
–Railwayreservationsystem
–Librarymanagementsystem
–Socialmediasites
–Telecommunications
–Onlineshopping
–Humanresourcemanagement

6. ELEMENT OF DATABASE
FIELDS:Afieldispartofarecordandcontainsa
singlepieceofdataforthesubjectoftherecord.
InthedatabasetableillustratedinFigure4,each
recordcontainsfourfields:

7. RECORDS:Dataisstoredinrecords.Arecordis
composedoffieldsandcontainsallthedata
aboutoneparticularperson,company,oritem
inadatabase.Inthisdatabase,arecordcontains
thedataforonecustomersupportincident
report.Recordsappearasrowsinthedatabase
table.ArecordforLogID1201242ishighlighted
inBelowmentionedFigure.

8. TABLES:Adatabasetableiscomposedof
recordsandfieldsthatholddata.Tablesarealso
calleddatasheets.Eachtableinadatabaseholds
dataaboutadifferent,butrelated,subject.

9. An Example of a Table
Records
Fields
Name GatorLinkPhone College
Graff rgraff 392-3900Pharmacy
Harris bharris 392-5555Medicine
Ipswich zipswich846-5656PHHP

10. KEYFIELD:Afieldofadatabase(typicallya
relationaldatabase)tablewhichtogetherform
auniqueidentifierforarecord(atableentry).
Theaggregateofthesefieldsisusuallyreferred
tosimplyas"thekey".

11. PRIMARY KEY
•Thecolumnorsetofcolumnsthatprovidethe
uniquenessfortherow.
•Atablecanhaveonlyoneprimarykey.
•Existingvaluesinprimarykeycolumnsmaynotbe
modified(insertnewvalueandthendeleteold
value)
•Thetableofarelationshipcontainingtheprimarykey
iscalledtheParentTable.

12. FOREIGN KEYS
•Aprimarykeyreferencedfromanothertableis
calledaforeignkey
•Foreachforeignkeyvalue,theremustbearowin
atablewhoseprimarykeyhasthesamevalue.
•Theforeignkeycanbemadeupofoneormore
columnsofatablebutmustmatchtheprimary
keyitisreferencing
•Atablecanhaveanynumberofforeignkeys.

13. PRIMARY KEYS & FOREIGN KEYS
Name User Phone College
Graff rgraff 392-3900Pharmacy
Harris bharris 392-5555Medicine
Ipswich zipswich846-5656PHHP
Toensurethateachrecordisuniqueineach
table,wecansetonefieldtobeaPrimaryKey
field.
APrimaryKeyisafieldthatthatwillcontain
noduplicatesandnoblankvalues.
ForeignKeyslinktodatainothertables

14. DATA MODELS
1.HIERARCHICAL
2.NETWORK
3.RELATIONAL
4.OBJECT

15. 1. HIERARCHICAL MODEL
Storesdataashierarchicallyrelatedtoeach
other.Recordshapearetreestructure.
BUET
Faculty of
Civil Engineering
Faculty of
Architectural
CE WRE URP Archit.

16. HIERARCHICAL DATABASE MODEL

17. HIERARCHICALDATABASEMODEL
•Logicallyrepresentedbyanupsidedown
tree
–Eachparentcanhavemanychildren
–Eachchildhasonlyoneparent

18. HIERARCHICAL MODEL
•Severalrecordsorfilesarehierarchicallyrelatedwitheach
other.Forexample,anorganizationhasseveraldepartments,
eachofwhichhasattributessuchasnameofdirector,number
ofstaffs,annualproductsetc.
•Eachdepartmenthasseveraldivisionswithattributesofname
ofmanager,numberofstaffs,annualproductsetc.
•Theneachdivisionhasseveralsectionswithattributessuchas
nameofhead,numberofstaff,numberofPCsetc.

19. Advantage and Disadvantages of
Hierarchical Model
Advantages
Highspeedaccesstolargedatabases
Easytoupdate-(toaddordeletenewnodes)
Disadvantages
LinksareonlypossibleinVerticalDirection(fromtopto
bottom)butnotforhorizontalordiagonalunlessthey
havesameparents.
Forexample,itishardtofindwhatistherelation
betweenURPandDCEfromthisdatamodel.

20. 2. NETWORK DATABASE MODEL
•Doesn’tforcedataintohierarchicallevels
•Owner/Memberrelationships:
–Ownerrecordtype
–Memberrecordtype
•Eachownermayhaveoneormoremembertypes
•Eachmembertypeandcorrespondingownerrecord
typeformset,whichrepresentsrelationship

21. Network Database Model

22. Network Database Model
•Each record can have multiple parents
–Composed of sets -relationships
–Each set has owner record and member record
–Member may have several owners
–A set represents a 1:M relationship between the
owner and the member
Figure 1.10

23. 3. RELATIONAL MODEL
•Based on two important
concepts:
–Key of relation-one to
one, one to many, many to
many
–Primary attribute–which
can’t be duplicate
Student
ID
Name CourseID
1 Mr. X 001
2 Mr. X 002
3 Mr. Y 003
Cour
seID
Title Cre
dit
001RS & GIS in WM 3
002Watershed Hydrology3
003Risk Management 3
Coursetable
StudentTable
Student Table Course Table
* *
Many to many relationship

24. WHAT IS A RELATIONAL DATABASE?
•Adatabaseismorethanjustacollectionof
information.Suchasstudentandcourseinformation,
facultyandgrades.
•Adatabaseisarepresentationofthepeopleand
thingsyourbusinessneedstooperate,andtheway
thosepeopleandthingsrelatetoeachother.
•Adatabasesystemsupportsthebusinessrules
definedbythecustomer.

25. RELATIONSHIP TYPES
1.One-to-One:relationshipissinglevaluedinbothdirections.A
managermanagesonedepartment;adepartmenthasonly
onemanager.
2.One-to-Many:relationshipismulti-valuedinonedirection-
onerowintheparenttableisassociatedwithmanyrowsin
thedependenttable.Onedepartmenthasmanyemployees.
3.Many-to-Many:relationshipsaremulti-valuedinboth
directions.Thistypeofrelationshipcanbeexpressedina
tablewithacolumnforeachentity.(crosswalktable)-An
employeecanworkonmorethanoneproject,andaproject
canhavemorethanoneemployeeassigned.Employee,
Project,andEmployee/Projecttables.

26. Relational Database Model

27. Relational Database Model
Figure 1.11

28. WHAT IS QUERY LANGUAGE?
•Querylanguage(QL)referstoanycomputer
programminglanguagethatrequestsand
retrievesdatafromdatabaseandinformation
systemsbysendingqueries.

29. WHAT IS QUERY ?
Aqueryisarequestforinformationfroma
database.

30. SQL
Whatisit?
StructuredQueryLanguage
•UsedinORACLEandotherDBsystems
•Non-procedural-i.e.Specifywhatyouwantnothow
togetit
•SQL-(alsopronouncedSEQUEL)
directlyrelatedtothedevelopmentofthe
RELATIONALMODELbyE.F.Codd.

31. SQL
•SQLisusedtoperformqueryinrelationsdatabases.
•Forexample,findthenameofthestudentwhotook
morethanorequalto6credithourinthisterm
SELECTStudent.Name,Course.Credit
FROMStudent,Course
WHEREStudent.CourseID=Course.CourseID
ANDCredit>=6
•Theansweris:
Mr.X6

32. Find the relationship between this two
tables in the BUET Library
ISBN Title Author
050 Applied
Hydrology
David
Maidmen
060 IrrigationCheng
ID Name ISBN
1 Mr. P050
2 Mr. Q060
3 Mr. R070
Book Table
Borrow Table
One to one
Many to Many
One to Many
?

33. Advantage of Relational Database
Advantages
thereisnoredundancy.
typeofbuildingofanownercanbechangedwithoutdestroyingthe
relationbetweentypeandrate.
anewtypeofbuildingforexample"Clay"canbeinserted.(rowinsert
iseasy).
Disadvantages
Requireanumberoftablesandrelationship
Itsdifficulttoaddanewcolumninthetable.

34. 4. OBJECT DATABASES
•Currentgenerationsystemshaveaneedtohandlecomplex
dataforcomplexapplicationssuchas
–computeraideddesign
–computeraidedsoftwareengineering
–geographicinformationsystems
–interactivewebsites
•Relationalsystemsareinadequateforthesesystems
–Whydoyouthinkthisis?

35. Object Database Types
•Object-oriented
–extendaprogramminglanguagesuchasJavawith
persistencyandaquerylanguage
•Object-relational
–extendacurrentRDBMS(e.g.Oracle)withobject-
orientedextensions

36. Object Oriented Model
BUET
Departments Institutes
CE
WRE
DCE IWFM
URP
AIT
Faculty, Staff, StudentsAttributes:
Is a
Is a Is a
Is a = Inheritance
Part of = association
Part of
Part of

37. OBJECT ORIENTED DATABASE
•AnObjectOrientedmodelusesfunctionstomodelspatialandnon-
spatialrelationshipsofgeographicobjectsandtheattributes.
•Anobjectisanencapsulatedunitwhichischaracterizedbyattributes,
asetoforientationsandrules.Anobjectorientedmodelhasthe
followingcharacteristics.
•GENERICPROPERTIES:thereshouldbeaninheritancerelationship.
•ABSTRACTION:objects,classesandsuperclassesaretobegenerated
byclassification,generalization,associationandaggregation.
•ADHOCQUERIES:userscanorderspatialoperationstoobtainspatial
relationshipsofgeographicobjectsusingaspeciallanguage.