The document discusses different types of database backups that can be performed at various levels, including full database backups, file group backups, file backups, differential backups, transaction log backups, tail log backups, and copy only backups. It also discusses that databases are not locked during backups, contrary to common misconceptions. The document then discusses key considerations for choosing a database management system (DBMS), including the data model, data consistency, security, protection, access, efficiency, usability, and costs of implementation and support. Finally, the document discusses logical database design, including mapping the conceptual model to logical constructs, normalization, defining integrity constraints, and validating the logical model against requirements. It also discusses centralized vs decentralized

1. Part A:
Ans 1. Differentlevelsatwhichdatabase backupscan be performed:
Full Database Backup:The firsttype database backupthatalmosteveryone isfamiliarwithisafull
backup.Whena full database backupistaken,thenall data files,file groups,andtransactionlogsare
backedup.A full database backupprovidesthe abilitytorestore the database tothe state that it
was at the time of the backup.
File GroupBackup: Everydatabase will have aprimaryfile groupwhichwill containthe primarydata
file.Considerafile groupafolderthatcan containzeroto manydata files.Tablesandindexesare
createdon file groupsandthe file grouphasdata filesthatthese objectsare thenstoredon.
File Backup: Every SQL Serverdatabase will containaminimumof one datafile,whichhasadefault
file extensionof “.mdf”anda logfile,whichhasan extensionof “.ldf“.The primarydatafile contains
all of the systemobjectsof thatdatabase and can containuserdefinedobjects.Additional files can
be addedto file groups,againtodistribute diskIOorto provide agranular meansof backupand
recovery.
Differential Backup: A differential backupbacksupall changesinthe database since the lastFULL
backup.If a full database backuphasnot beentaken,thenthe differentialwillfail.Keepinmindthat
the differential backuprecordsall changessince the lastFULLbackup soif a full backupistakenat
midnightanda differentialistakenat0100, 0200, 0300, and 0400, the differentialbackup takenat
0400 will containeverythingthatthe 0100, 0200, and 0300 have.
Transaction Log Backup: A transactionlogbackupbacks upthe active portionof the transactionlog.
The database recoverymodel mustbe setto full orbulkloggedanda full,file, orfile groupbackup
mustfirsthave beentaken.Afteratransactionlogbackup istaken,the transactionlogwill be
truncated.
Tail Log Backup: The tail logbackupis a transactionlogbackup,HOWEVER it isthe backup of the
transactionlogthat istakenbefore beginningthe restorationprocess.The syntax isidentical toa
transactionlogbackup,exceptthe clause WITH NORECOVERYisaddedthattellsSQLthat the
database isabout to be restored.
Copy OnlyBackup: A copy onlybackupisa full database backupEXCEPTthat IT isindependentof
the sequence of conventional SQLServerbackups.Usually,takingabackupchangesthe database
and affectshowlaterbackupsare restored.
Database Locks During Backups: Thisisa myth.SQL doesnotplace any lockson the database during
a backup.This misconceptionmostoftenarisesbecauseyoumaysee degradationinperformance
duringa backup.This isdue to diskIO,the readingof the filesandwritingtothe backupfiles,and
not due to locking.
Ans 2. Havinga perfectlyfittingdatabase managementsystem(DBMS) isakeycomponentfor
today’sbusinesssuccess.The DBMSmanagesthe interactionbetweenyourapplicationsandthe
underlyingdatabase.Itassuresthatthe correct data isavailable forthe requesteduser groupwhen
needed.WhenchoosingaDBMS fromthe varietyof conceptsand vendors,youshouldconsiderthe
followingpointsbefore makingadecision.

2. Data Model:For a longtime,the relational conceptwasdominant,howeverrecentlyNoSQL
databaseshave againbecome more successful.Relational vs.NoSQLisbasedonyourindividual
needsandtheirmainadvantage isthe data structure itself.Todecide onwhichmodel worksbestfor
you,youshouldask yourself:Doyouhave a data structure whichyoucan easily reflectinarelational
model ordo youneedto workwithunstructureddata?How doyou retrieve andworkwiththe
data? For example,analysisof hierarchical datainsequential filesisfasterinaNoSQL database then
ina relational one.Sincerelational databaseshave alonghistory,youfindalotof commercial
RDBMS (relationalDBMS),whereasNoSQLdatabasesare oftenavailableasopensource.
Data Consistency:Nowadays,collectingdataisnota big effortanymore.But,keepingthe data
consistentbecomesevenmore importantasmore sourcesfeedintothe database.Therefore,
consistencyrulesare veryimportantandthe abilitytodefinethese shouldbe consideredwhen
choosinga newDBMS.
Data Security: For mostcompanies,dataavailabilityisakey businesssuccessfactorandshouldbe
guaranteedatall times.The abilitytobackupand restore the databasesisessentialandneedstobe
possible withyourchosenDBMS.IT Administratorsshouldsetupaframeworkanda management
planfor data security andensure aslittle downtime aspossible.
Data Protection:Accessprotectionandencryptionshouldallow protectionof personal data.Every
DBMS provide differentmethodsof protectthe datathroughencryption,butthe possibilityto
define routinesand accessrightsisdifferentforeverysystem.The methodof dataprotection
dependsonthe structure of data and shouldbe carefullyconsideredduringthe evaluationprocess
of a DBMS.
Multi Access and Integration: Settingupa DBMS, runningitand extendingitforfuture growth,
requiresenoughflexibilitytoallowintegrationintothe givenITinfrastructure.Furthermore,the
DBMS needstoallowconcurrentaccessesbymultiple users.Synchronizationandintegrationwith
othertoolsare essentialforsmoothworkflows.
Efficiency:Whenwe talkaboutthe efficiencyof DBMS,we usuallymeanthe response time.Youwill
findonpremise andcloudsolutionsavailableonthe market.DependingonyourownIT
infrastructure,acloudbasedsolutioncanhave certaindisadvantages,asyourelyonnetwork
servicesandlatenciesof networkproviders.Onthe otherside,cloudcomputingcanprovide more
and betterresourcescomparedtoyouron premise infrastructure,asefficiencyisalsorelatedto
scalability.Make sure yourDBMS of choice can scale to yourneeds.
Usability:Differentusergroupswill be workingwiththe DBMS.There are the administrators,ITand
Database admins,applicationintegratorsanddataconsumers.All these differentrolesneedan
easilyunderstandablequerylanguageandintuitive UItouse the DBMS systemefficiently.The easier
it isfor the userto workwiththe DBMS, the lowerthe costwill be forpeople.

3. ImplementationandService Costs: The modifiabilityandavailabilityof supportanddocumentation
needstobe takenintoconsiderationaspart of the implementationandTotal Costof Ownership
(TCO).Developmentneedsmustalwaysbe included,asDatabase ManagementSystemsneedtobe
shapedtothe individual company’sneed.A clearoverview of theseneedsandcostswill helpto
choose the righttool.Vendororcommunitysupportas well ascomprehensivedocumentationwill
save youtime and money.
Ans 3. Logical designisthe secondstage inthe database designprocess.The logical designgoal isto
designanenterprise-widedatabase basedonaspecificdatamodel butindependentof physical-
level details.Logical designrequiresthatall objectsinthe conceptual model be mappedtothe
specificconstructsusedbythe selecteddatabase model.Forexample,the logical designfora
relational DBMSincludesthe specificationsforthe relations(tables),relationships,andconstraints
(i.e.,domaindefinitions,datavalidations,andsecurityviews).
The logical designisgenerallyperformedinfoursteps,whichare asfollows.
1. Map the Conceptual Model to the Logical Model: The firststepincreatingthe logical designisto
map the conceptual model tothe chosendatabase constructs.Logical designgenerallyinvolves
translatingthe ER model intoaset of relations(tables),columns,andconstraintsdefinitions.The
processof translatingthe conceptual model intoasetof relationsisdepictedasfollows.
 Map strongentities
 Map supertype/subtyperelationships
 Map weakentities
 Map binaryrelationships
 Map higherdegree relationships
2. Validate the Logical Model UsingNormalization: The logical designshouldcontainonlyproperly
normalizedtables.The processof mappingthe conceptual modelto the logical model mayunveil
some newattributesorthe discoveryof new multivaluedorcomposite attributes.Therefore,it’s
verylikelythatnewattributesmaybe addedtotablesorentire new tablesaddedtothe logical
model.Foreachidentifiedtable (oldandnew),youmustensure thatall attributesare fully
dependentonthe identifiedprimarykeyandthatthe tablesare in at leastthirdnormal form(3NF).
3. Validate Logical Model IntegrityConstraints: The translationof the conceptual model intoa
logical model alsorequiresthe definitionof the attribute domainsandappropriate constraints.For
example,the domaindefinitionsforthe CLASS_CODE,CLASS_DAYS,andCLASS_TIME attributesof
the CLASS entityare writtenthisway:
CLASS_CODEis a validclasscode.
Type:numeric
Range:lowvalue = 1000 highvalue = 9999
Displayformat:9999
Length:4
CLASS_DAYSisa validdaycode.

4. Type:character
Displayformat:XXX
Validentries:MWF,TTh, M, T, W, Th,F, S
Length:3
CLASS_TIME is a validtime.
Type:character
Displayformat:99:99 (24-hour clock)
Displayrange:06:00 to 22:00
Length:5
4. Validate the Logical Model against User Requirements: The logical designtranslatesthe
software-independentconceptualmodelintoasoftware-dependentmodel.The finalstepinthe
logical designprocessistovalidate all logical model definitionsagainstall end-userdata,transaction,
and securityrequirements.The stage isnow setto define the physical requirementsthatallow the
systemtofunctionwithinthe selectedDBMS/hardware environment.
Ans 4. CentralizedDatabase Design: For a small organizationandlimitedscope of operations,the
database maybe small intermsof data. Therefore,the database designmaybe relativelysimpleand
can be easilydone byone groupof designerorevenasingle person.Thisiscalledcentralizeddesign
of database.The designercanstudythe systemprocesses,identifythe constraints,andcreate
conceptual schema,whereasthe userscanverifyittoensure thatthe database meetstheirneeds
and processingrequirements.
DecentralizedDatabase Design:Whenthe database studyrevealsthatthe resultingdatabase isfor
the ‘whole organizationsandthatit haslarge numberof entitiesandcomplex relationsonwhich
verycomplex operationsare performed,thenthe database designmaybe undertakenbydivisionof
work.Here it may be suitable tostudyanddesignconceptual schemaforeachdepartmentor
functionforwhichthe database isto be designed.The database designprojectmaybe thoughtof as
one large projectsubdividedintosmallermodules,and eachmodule isdesignedbyagroup of
people.
Each module isinitself asystemandmustmeetthe systemrequirementsasawhole.These modules
whenintegratedtoforma single database mustmeetthe processingrequirements.Thisiscalled
decentralizeddesignapproach.Thisapproachisalsosuitable whenthe database designisspread
across several operational sites,andeachelementisasubsetof the entire dataset.

5. Part B:
Ans1. (1) a.
b.

6. c. There are 4 relationsin the "TAL_Distributors" database.
d.
Name of the
relation/Table
No of attributes Namesof the attributes
1. Customer 9 CustomerNum,
CustomerName,
Street,
City,
State,
PostalCode,
Balance,
CreditLimit,
RepNum
2. Item 6 ItemNum,
Description,
OnHand,
Category,
Storehouse,
Price
3. OrderLine 4 OrderNum,
ItemNum,
NumOrdered,
QuotedPrice

7. 4. Orders 3 OredrNum,
OrderDate,
CustomerNum
5. Rep 9 RepNum,
LastName,
FirstName,
Street,
City,
State,
PostalCode,
Commission,
Rate
(2) a.

8. b.
Name of the
relation/Table
No of
attributes
Namesof the
attributes
PrimaryKey
1. Customer 9 CustomerNum,
CustomerName,
Street,
City,
State,
PostalCode,
Balance,
CreditLimit,
RepNum
CustomerNum
2. Item 6 ItemNum,
Description,
OnHand,
Category,
Storehouse,
Price
ItemNum
3. OrderLine 4 OrderNum,
ItemNum,
NumOrdered,
QuotedPrice
OrderNum,
ItemNum
4. Orders 3 OredrNum,
OrderDate,
CustomerNum
OredrNum

9. 5. Rep 9 RepNum,
LastName,
FirstName,
Street,
City,
State,
PostalCode,
Commission,
Rate
RepNum
c.
d.

10. e.

11. (3) 1.
a.
SELECT *
FROMCustomer
b.
SELECT *
FROMItem
c.
SELECT Customer.CustomerNum,Customer.CustomerName
FROMCustomer;
d.
SELECT Customer.CustomerNum,Customer.CustomerName,Customer.RepNum
FROMCustomer
WHERE (((Customer.RepNum)="15"));
e.
SELECT Customer.CustomerNum,Customer.CustomerName, Customer.RepNum,
Customer.CreditLimit
FROMCustomer
WHERE (((Customer.RepNum)="15") AND((Customer.CreditLimit)=10000));
Ans. 2
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