DATA MANAGEMENT.pptx

7/24/2019 DATA MANAGEMENT.pptx

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USE OF ICT INDATA

MANAGEMENT


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What is a database?

It is a collection of elated data!

It consists of ecods and "elds# each ecodcontains the sa$e set of "elds!

One "eld contains one %iece of info$ation!


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Processing arecord

Sequential Files

Functions in aSequential File

Index Sequential andRandom Access File

DatabaseManagement

System

PerformingFunctions

Hierarchical

DatabaseManagement

System

Netor!Database

ManagementSystem

RelationalDatabaseSystem


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Database Mana&e$entS'ste$ (DBMS)

This is a kind of soft*ae that is +sed to

$ana&e database s'ste$s, St+ct+e of indi-id+al data "les

.elationshi%s bet*een data ite$s /bet*een data "les

0o* data is seached (inteo&ated)

1o%eties of the database (2+eies3+%datin& o a$end$ents)


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Se2+ential Files

.ecods ae stoed one afte the othe in theode the' *ee added to the stoa&e $edi+$!

Stoa&e Medi+$, Ma&netic Ta%e

T*o *a's in *hich ecods can be aan&ed,4! 0a-e the ecods in an ode +sin& a ke'

"eld!

What is a ke' "eld?

Its is +ni2+e fo e-e' ecod! It is e2+ied toens+e that 'o+ don5t ha-e an' d+%licates!

This t'%e of t'%e of se2+ential is

called


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Se2+ential Files6! Anothe *a's is to aan&e the ecods in no

%atic+la ode

This is t'%e of se2+ential is called

unordered sequential!Anothe na$e fo an +nodeed "le is serial

"le!

Thee is onl' one *a' of accessin& the data, b'

&oin& tho+&h each ecod one b' one!


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Se2+ential Files

Odeed "le 77 8 data is %+t in ode of a ke' "eld(For example: customer ID)

Unodeed "le 77 8 as the na$e s+&&ests as thedata in no %atic+la ode!

Disad-anta&es of +sin& se2+ential "les


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Random #s$ Sequential


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Disad-anta&es of a

Se2+ential File4! 9o+ can onl' add a ne* ecod at the end of

the "le

6! If a ecod needs to be replacedit $+st bethe E:ACT sa$e len&th as the oi&inal

;! A ecod can onl' be updated if the dataite$ +sed to e%lace the e


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0o* do 'o+ %ocess

ecods? 9o+ need to ead tho+&h each and e-e' ecod+ntil 'o+ &et the one 'o+ *ant!

Only recommended for applications wheremost/all the records are to be processed at onetime.

For example: British Gas sends out bills to all

their customers. ou recei!e a bill after e!erythree months. "o a person who #oins in $anuarywill recei!e their bill in %pril alon& with all theother people who also #oined in $anuary.


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F+nctions in a Se2+ential

File Addin& ecods 77 8 eas' A$endin& / Deletin& 77 8 not so eas'!

If it is an +nodeed se2+ential "le a$endin&and deletin& ae fail' di>ic+lt

If it is an odeed se2+ential "le a$endin&and deletin& ae sot of eas'! This is done *iththe assistance of a tansaction "le!

What is a tansaction "le?It contains the actions to be caied o+ton the ecods!


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1efo$in& F+nctions in

an Odeed FileThe ke' "eld is +sed!Master File

ID

Name %ender

4 M Ah$ed Male

6 Ms.+ssell

Fe$ale

; M .o'ale Male

= M O5Neil Male

&ransaction File

ID Tans!

Na$e Gende

4 D M Ah$ed Male

6 C M .+ssell Male

; D M .o'ale Male

A 0a"@ MaleNe Master File

ID

Name %ender

6 M.+ssell

Male

= M O5Neil Male

0a"@ Male

Co$%+te eads the "st

ecod fo$ thetansaction and the$aste "le! If the ID

doesn5t $atch (In this caseit does)3 the co$%+te

*ites it to the ne*$aste "le

The ne


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Inde


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Inde


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Inde


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Inde


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S'()'N&IA* FI*'S IND'+'D FI*'S

Se2+ential "les ae called as SAM"les!

Inde


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0ieachical DatabaseMana&e$ent S'ste$s (DMS)

No lon&e +sed! Wh'?

One7*a' elationshi% %oble$ A hieachical DMS 77 8 fa$il' tee like

st+ct+e!

One mother can ha!e many children' but thechildren can ha!e only one mother.(

indows system se!eral users eachuser will ha!e se!eral documents

Enablin& fast access to data


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Net*ok DatabaseMana&e$ent S'ste$ (DMS)

O-eco$e the fa+lts of the hieachical DMS

Man' o&anisations no* +se a distib+teddatabase s'ste$!

Data is stoed on co$%+tes that ae thenlinked b' a HANWAN!

Data in the database is d+%licated se-eal

ti$es3 so it is +nlikel' to loose the data andit also &i-es the +ses faste access ti$es!

To a +se it see$s to be a sin&le s'ste$


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S'ste$ cates fo co$%le< seaches#seach is not necessail' done at the site*hee the +se is!

For example: somethin& that is done inDu*han on our computers could be thenprocessed in Doha.


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Anothe t'%e of Net*ok DB stoedon one de-ice accessed fo$ a n+$beof net*ok locations!

Uses access the database b+t don5tslo* the s'ste$ do*n!

For example: +,- +olice ,ational-omputer) and D0% Dri!er andehicle 0icensin& %uthority)


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.elational DatabaseS'ste$s

What is a elational database?

It consists of se%aate tables that ae allelated in so$e *a'! So this $eans thateach table needs to ha-e a ke' "eld thatis a "eld in anothe table! So *hat?

The data fo$ the initial table can then beco$bined *ith data fo$ anothe table*hen 'o+ need to %od+ce e%ots!


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,ustomerC+sto$e ID

Na$e,

Date of Bith,

Addess,

Tele%hone N+$be,

D-DDD ID

Na$e of DD,

N+$be of Co%ies,

Main Acto,

C+sto$e ID

In this table theC+sto$e ID is the

e' Field

In this table the DD ID isthe %i$a' ke'! The

C+sto$e ID is the foei&nke'! These t*o tables aelinked b' the C+sto$eID!


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Standad 1o&a$$in& Han&+a&e dealin&*ith elational tables is called St+ct+ed+e' Han&+a&e (SH)! What is it +sed fo?

It is +sed fo 2+eies and %od+cin& e%ots!

Ad-anta&es of elational databases


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Ad-anta&es of .elationalDatabases

4! Data not e%eated stoa&e ca%acit' not*asted! Co$%ain& this to a Jat "le

database3 in *hich data is e%eated!6! Data etie-al is 2+icke! If the data is

e%eated3 hackes *ill ha-e &eate ease inaccessin& the data! .elational databases

ed+ce this isk!;! The' also allo* oo$ fo e

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