Overview of Database System

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I-1 Copyright © Oracle Corporation, 2001. All rights reserved.

Database Management

System



2Copyright © Oracle Corporation, 2001. All rights reserved.

An Overview of Database

System

Lesson 1




What is Data?

•A collection of rawfacts, figres, !symbols" If a lot ofaccrate #ata is$rocesse# correctly,

we get valableinformation"

– %mbers

– Wor#s

– Images – &i#eo

– Son#s



I-' Copyright © Oracle Corporation, 2001. All rights reserved.

What is Data?

• (em$eratre, $ressre, rainfall an# win#s$ee# #ata can be $rocesse# to give aweather ma$"

• %ames an# a##ress of em$loyees is #atathat can be $rocesse# to give )ersonnelInformation"

• In a De$artment Store, the #ata abot

items sol#, their $rice, *antity an##e$artment names can be $rocesse# to

give management information"



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What is a #atabase?

A #atabase is a collection of#atainformation that is store# for as$ecific $r$ose an# organie# in amanner that allows its contents to beeasily accesse#, manage#, an# $#ate#"Althogh this #efinition incl#es store##ata collections sch as libraries, filecabinets, an# a##ress boo.s, when wetal. abot #atabases we almost invariablymean a collection of #ata that is store# ona com$ter"



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(wo basic categories of #atabase

• (he most commonly encontere# category is thetransactional database, se# to store #ynamic#ata, sch as inventory contents, which is

sb0ect to change on an ongoing basis" (heother category is the analytical database, se# tostore static #ata, sch as geogra$hical orchemical test reslts, which is rarely altere#"


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2am$le of #atabase St#ent Data

StudID FirstN LastN I Address City Telno CourseID

S12004 Jove Easley P 133 1st Street Ne !or" 4#$212$ %SCS1

S21&&& Jane S'it( E 434 4t( Street Los An)eles 4#21410 %SC*E3

S32000 +andy Doe * 143 2nd Street Detroit 321#444 %S%A2

S42001 ,eor)e -arley S ### 1st Street C(i.a)o 4##1//1 P+*,1

4iel#s

5ecor#s6ell

(able


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(here are five sim$le things that nee# to

be #one with the recor#s in the #atabase 8

• A## new recor#s 9create, ma.e, insert:

• Delete nwante# recor#s 9erase, $rge,remove:

• ;$#ate eisting recor#s 9alter, mo#ify,change:

• Sort the recor#s in any or#er 9reor#er, gro$:

• Search for recor#s that match a criteria9select, access:"


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2nter$rise

• A #atabase is a collection of $ersistent #atathat is se# by the a$$lication system ofsome given enter$rise" (he term

=enter$rise> here sim$ly a convenientgeneric term for any reasonably selfcontaine# commercial, scientific, technicalor other organiation" An enter$rise might

be a single in#ivi#al or similar large bo#y"



@ere are some eam$les8

–A manfactring com$any

–A ban.

–A hos$ital

–A niversity

–A government #e$artment



)ersistent Data

• Any enter$rise mst necessarilymaintain a lot of #ata abot itso$eration" Sch #ata is =$ersistent#ata>" An enter$rise wol# ty$icallyincl#e the following among their$ersistent #ata8



)ersistent Data

–A )ro#ct #ata

–Accont #ata

–)atient #ata

–St#ent #ata

–)lanning #ata



Database System?

• A Database System is s$ecial #ata$rocessing system or $art of the #ata$rocessing system which ai#s in thestorage, mani$lation, re$orting,management ! control of #ata"


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6om$onents of Database

System –Data an# Information

–Software

–@ar#ware


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6om$onents of Database

System-;sers

1" A$$lication $rogrammers

" 2n# sers

3" Database administrator (DBA) – Defining eternal schema

– Defining conce$tal schema

– Defining internal schema

– Biaison with sers

– Defining secrity an# integrity chec.s

– Defining bac.$ an# recovery $roce#res

– Monitoring $erformance an# changingre*irements


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Data

• is a re$resentation of facts, conce$ts, orinstrctions in a formatte# manner sitable forcommnication, inter$retation or $rocessing byhman beings or by atomate# means"

• Data8 5aw 4acts, in a form of tet, gra$hics,images, son# an# vi#eo segments that havemeaning in the serCs environment"2" Bist of em$loyees

ing

Allen

Ela.e



@ierarchy of #ata

– Eits8 Einary #igits which vale of either or1, it is the smallest nit of #ata in acom$ter"

– Eyte8 A gro$ of that form information, a

se*ence of 7 bits" – 6haracter8 Al$hanmeric nit of #ata"

– 4iel#8 is the smallest logical fiel# of #ata"

– 5ecor#8 6ollection of relate# fiel#s"

– 4ile8 6ollection of relate# recor#s"

– Database8 6ollection of relate# #ata in a file"



Information

• Data that have been $rocesse# in sch away as to increase the .nowle#ge of the$erson who ses the #ata"

Data in contet F e" )ayroll re$ort

Smmarie# #ata F e" Gra$h or 6hartre$ort


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Software

• DES Sot!are is the $rogram that #efinesan# manages a #atabase, stores the #ata,s$$orts a *ery langage, $ro#ces

re$orts, an# creates #ata entry screens"


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@ar#ware

• DES "ard!are is the $hysical #evice which iscom$ose# of the secon#ary storage volmes Fmostly magnetic an# com$act #is. F that are se#to hol# the store# #ata, together with the

associate# IO #evices 9#is. #rives, etc":, #evicecontrollers, IO channels, an# so forth" Another oneis the har#ware $rocessor9s: associate# with mainmemory that are se# to s$$ort the eection ofthe #atabase system software"



DES ;sers

– System analyst re*irement analysis – Database #esigner generate #ata mo#el

– A$$lication $rogrammer im$lement thetransactions an# ser interface

– )ro0ect manager monitor the $rogress of theim$lementation

– 2n# ser eecte transactions

– Database a#ministrator tne the #atabase

$erformance

– System a#ministrator monitor the system$erformance an# $#ate softwarehar#ware whennecessary



I- Copyright © Oracle Corporation, 2001. All rights reserved.

4eatres of a DES

– A #ata mo#elling $ara#igm 5elational DataMo#el

– Mathematical fon#ations of #atabase #esign

– @igh level $rogramming langage SHB

– Many im$lementations

– Other #ata mo#els eist, an# are being #evelo$e#

– %etwor., ob0ect-oriente#, MB

– DEMS stores a rich set of #ata ty$es images,tet, a#io an# vi#eo, geogra$hic #ata

– DEMS $rovi#es online access re*ests are$rocesse# at the time they are initiate#




4eatres of a DES

– DEMS allows concrrent access mlti$le

transactions may be $rocessing at the same time – DEMS may involve #istribte# #ata a single

transaction may nee# to access mlti$lenetwor.e# sorces

– DEMS may involve #istribte# $rocessingcom$le o$erations are not necessarily carrie#ot where the #ata is store#

– DEMS a$$lication may be heterogeneos a

single a$$lication may s$an mlti$le DEMSim$lementationssystems



I-' Copyright © Oracle Corporation, 2001. All rights reserved.

DES 4nctional Strctre

• (he =#ront$%nd>

– ;ser-written a$$lications

– embe##e# *eries

– re*ires DEMS A)I to lin. nativelangage with DEMS langage

– DEMS a$$lications

– #irect access to DEMS *ery $rocessor

– re$ort writers

– natral-langage *ery $re-$rocessors



I-+ Copyright © Oracle Corporation, 2001. All rights reserved.

DES 4nctional Strctre

• (he =&ac'$%nd>

– (he DEMS itself

– *ery $rocessor

– secrity, concrrency, integrity

– #ata #efinitions, view #efinitions



I-/ Copyright © Oracle Corporation, 2001. All rights reserved.

Sam$le DES?

– S$$ose we are constrcting a =St#ent5egistration System> with the followingfnctionalities for st#ents an# faclty8

– ;sers athenticate themselves

– 5egister for corses offere# net semester

– Obtain re$orts on $articlar st#entCs stats

– Maintain information abot st#ents an#corses

– 2nter final gra#es for corses that a st#enthas com$lete#




2voltion in DEMS

#)L% ")%+A+C")CAL %(-O+ +%LA()OAL O&/%C( O+)%(%*

AL)CA()O

*A(A

DBMS History



I-< Copyright © Oracle Corporation, 2001. All rights reserved.

6ontining (echnical 2voltion

– 103s4 #ile processing 5CO&OL6

– 1703s4 +elational *atabases on )&8 8ainra9es5*&2 and S:L6

– 1;03s4 +el *&8S or 8icros 5+$&AS%, *&AS% )),

etc...6

– 103s4 <ative= Client$Server, Ob>ect$Orientation5CO+&A, O+ACL% o!er Ob>ects6 Co99on Ob>ect+e?@est &ro'er Architect@re "

– 20003s4 /ava$driven <on native= Client Server58any prod@cts in develop9ent6




2am$les of DEMS

A$$lications

– Oracle

– )ngres

– )nor9iB 5niB6

– 8ys?l

– *&2, S:LD*S 5)&86

– Access 58icrosot6

– S:L Server 58icrosot E6

– 8any older 5#oc@s, )8S, ...6

– 8any li9ited C 5d&ase, aradoB, F6




A#vantages of

Database A$$roach

– 8ini9al data red@ndancy.

– *ata consistency.

– )ntegration o data.

– Sharing o data. – #ast, better and standard data access

– %norce9ent o standards.

– (ransaction s@pport

– %ase o application develop9ent and 9aintenance.

– nior9 sec@rity, privacy and integrity.

– *ata and progra9 independence.




Drawbac.s of ol# 4ile metho#s

– ncontrolled *@plication

– -astes space

– "ard to @pdate all iles

– )nconsistent data

– )nleBibility

– "ard to change data

– "ard to change progra9s

– Li9ited data sharing

– oor enorce9ent o standards

– oor progra99er prod@ctivity

– %Bcessive progra9 9aintenance



;se a DEMS when this

is im$ortant• $ersistent storage of #ata

• centralie# control of #ata

• control of re#n#ancy

• control of consistency an#integrity

• mlti$le ser s$$ort

• sharing of #ata

• #ata #ocmentation

• #ata in#e$en#ence

• control of access an#secrity

• bac.$ an# recovery

Do not se a DEMS

when the initial invest9ent in

hard!are, sot!are, and trainingis too high

the generality a *&8S provides

is not needed

the overhead or sec@rity,

conc@rrency control, and

recovery is too high

data and applications are si9ple

and stable

real$ti9e re?@ire9ents cannot be

9et by it

9@ltiple @ser access is not

needed

Overview of Database System

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