QR.Data Froqmentation and Raplicahion
Data Fragmentation
Data Fragnentationis the poA of disintagratin g
relatond or tables nto Seeral parhihions.
LH divides the alata into
Sub tablesS0.
dhat
sUb relatond anol
vaious
thedata
can
be
alistnbuteo
Land sod efoiunthy
Fragmantatian is the prnce
S
into
Set of
The subsets o
he
of dlividing
a table
Smallr tables
table
ar aalled fognents
Fragmantahon an be of 3 typed
’
Horizontal Frag mentation
Vutical
Frogmentation
Hybid FragmantaHan.
FraamenBation should be alone in Such a way that
the oniginal table
ragments
Thi's
can bereconstucfeo from the
s caled
Ureconstuctiveness"
Let vs consiolera universiy that kanps rrcorad of
all ngistered stulnts in a huolnt table hain
the following shema
STUDENT
Reg-ne
Noume
Oaurse
Addres
Semester
Fees Mak
Horizontal Fragmuntation
Horizental Fragmantahion graups the tples of a table in
accordane
to
table for
original base
felola
more
One
haizental togmaat
Each
eq.
valved
must
have
all the
co lurm ng of the
reconstrvchvenes
schema f the oletails of all stuclents of
Computer scienoe OUrse need to be maintaçned at
n shdent
Sohoal of computer Sciena
honizontally fagmented
CREATE
0MP
STD
FROM
SELEC
then
the databae oan be
fallaus -
AS
STUDENT
c0URSE E "Computur Science
WHERE
Vertical Fragmuntation
The feloA or columns of
gragmants in
To
maintan recensthuehvend
dhe priman
e
a table
Yerhoal fagmunt ation
are grouped into
each ragmnt should contan
kuy fud) of the fable
saf the fee oletais nud to be
accounts
Sechion, thun
the
fagmanted
CREATE
TABLE
STD FEES AS
Keg-no,Fees
FROM 8TUDENT
SELE C
olatabaue
maint ainad in Hhe
aan be vethially
Hybrid Frngmutation
&t is o
oombinahonof
horizental cnd vortical
fagaentation techniquct.
the most fiexible fragnnantation tuchnique, an
au.
This is dee
it generotek rognants uith
minimal extraneous
Linformaiorn.
Howv
reconuhvchon of the
is often
original
on xpensive tak
altornahive wys
Frst gunerate a set of horizontal ragments, then
gunante vethical ftag meats em One Or nore
harizental fagments
OR
of varti cal fragmnts, then
rst qeneate
erate harizontal rognmants fom
vetical agments.
one or more of Hha
ddvantags of Fragnmantatian
Sina oato is stored olose to the site of Usage, effcleny
of the databoe is inoreaAed
Since imlevont oata is not available at dhe site.
Secunihy and privaoy
DisadvoantagA of
of thedatabaue
be
maintalned
Fragmentahan’
When data from different frag ments
re required, acce
speeds may be ey low
’ n case
will nud
of recursive fragmntation
punaire tchaiquus.
econsuchon
Replicahon
Data
the prncu afstoringSeparatL capidofthe
databae at
St is
two
or
more
a populau fowlt
site
toleran oe techaique of sishibuteo
database
Commanls sed replication tehniqut include
Snap shot rplicaion
near -real tinne rplication
pull eplicahion.
Aolvountaqu of Data Ruplicatian
Reliabilihy - Sn case of failure at ony site, the database.
System continue to lwork sinc a copPy is
Qvoilable
Reducti.n in
Network
are availabl
at
another si.
local capiAA of data
4ueny pncLssing an be olone
koao-
Sin e
with reducud natuork vaage
pim hurs
Data updating
particularty duning
on be olo
atnon
prime hours
Availabilihy of ocal aapies
Quicker Rupsnse
quicker uy prneLMing and thua qui cker esponse
imes
Simpler Trana achan
RUNburof
TroAachianu require eade, joind f
tables located at diffrnt sites
bece me simpler in natur
thus
they
Disod vantages of Dota Replication ’
Sncreased Storage requiremants- malnting
of the data is oociatud
mulhiple capiea
with 0noreased
Storage costs. The storage space requird is in
multiples af the space nquitzd fora centaliu
Systum
Inorasedcat and complexity of dlata updahing Each
ime the dlata is upolated
the update
must
eAect in all capies at dlifeurnt sites. This requines
complex synchonization tuhniquee and praaeala
Sf complex synchto ni zahionmechanisms ae nat escd,
emoving data in consist anay requirs
at applicahonlevel.
complxcoorainaton