Solutions manual for database systems design implementation and management 12th edition by coronel All Chapters 1-16

Appendix tC tThe tUniversity tLab:
Conceptual tDesign tVerification, tLogical tDesign, tand tImplementation

Appendix C t




The University Lab: Conceptual Design,
t t t t



tVerification,Logical Design, and Implementation
t t t t




Discussion tFocus


How tis ta tdatabase tdesign tverified, tand twhy tis tsuch tverification tnecessary?



Use tour tdetailed tanswer tto tquestion t1 tto tfocus tclass tdiscussion ton tdatabase tdesign tverification. tStress
tthat tthe tverification tprocess tuses tthe tinitial tER tmodel tas ta tcommunication ttool.




The tdesigner tmay tbegin tthe tverification tprocess tby tdescribing tthe torganization's toperations tto tits tend
tusers, tbasing tthe tdetailed tdescription ton tthe tinitial tER tmodel. tNext, texplain thow tthe toperations twill

tbe tsupported tby tthe tdatabase tdesign. tStress tthat tthe tdesign tmust tsupport tthe tend-user tapplication

tviews, toutputs, tand tinputs. tPoints tto tbe taddressed tinclude tsuch tquestions tas:



 Is tthe tdescription taccurate? tIf tnot, twhat taspects tof tthe tdescription tmust tbe tcorrected?
 Does t the t model t support t the t end-user t requirements? t If t not, t what t aspects t of t the
t end-usertrequirements thave tnot tbeen taddressed tor thave tbeen taddressed tinadequately?




Keep t in t mind t that t even t a t model t that t perfectly t addresses t all t initially t determined t end t user
t requirements tis tlikely tto tneed tadjustments tas tthose tend tusers tbegin tto tunderstand tthe tramifications

tof tthe tdatabase tdesign's tcapabilities. tIn tmany tcases, tthe tend tusers tmay tlearn twhat tthe torganization's

tprocesses tand tprocedures tactually tare, tthus tleading tto tnew trequirements tand tthe tperception tof tnew

topportunities. tThe tdatabase tdesigner tmust tkeep tsuch tlikely tdevelopments tin tmind, tespecially tif t(s)he

tworks tas ta tdatabase tdesign tconsultant. t(Anticipation tof tsuch tdevelopments tmust tbe tfactored tinto tthe

tcontract tnegotiations tfor tconsulting tfees.)




Discuss tthe trole tof tthe tsystem tmodules.



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, Appendix tC tThe tUniversity tLab:
Conceptual tDesign tVerification, tLogical tDesign, tand tImplementation


The t use t of t system t modules t can t hardly t be t overemphasized t in t a t database t design t environment.
t Stresstthese tmodule tcharacteristics tand tfeatures:



 Modules trepresent tsubsets tof tthe tdatabase tmodel: tSmaller t"pieces" tare tmore
teasilytunderstood.

 Modules tare tself-contained tand taccomplish ta tspecific tsystem tfunction; tif tsuch ta tsystem
tfunction tmust tbe tmodified, tother tfunctions tremain tunaffected.

 Modules tfit tinto ta tmodular tdatabase tdesign, twhich tis tmore teasily tmodified tand tadapted
tto tnew tcircumstances. tBecause tmodification tefforts tare tfocused ton ta tdatabase tsubset,

tproductivity tof tboth tdesigners tand tapplication tdevelopers tis tlikely tto tbe tenhanced.




Module tinterfaces tmust tbe tclear tif tthe tmodules tare texpected tto twork twell twithin tthe toverall tsystem.




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, Appendix tC tThe tUniversity tLab:
Conceptual tDesign tVerification, tLogical tDesign, tand tImplementation

Answers tto tReview tQuestions


1. Why tmust ta tconceptual tmodel tbe tverified? tWhat tsteps tare tinvolved tin tthe tverification tprocess?


The tverification tof ta tconceptual tmodel tis tcrucial tto ta tsuccessful tdatabase tdesign. tThe tverification
tprocess tallows tthe tdesigner tto tcheck tthe taccuracy tof tthe tdatabase tdesign tby:



 Re-examining tdata tand tdata ttransformations.
 Enabling t the t designer t to t evaluate t the t design t efficiency t relative t to t the t end t user's
t andtsystem's tdesign t goals.




Keep tin tmind tthat, tto ta tlarge textent, tthe tbest tdesign tis tthe tone tthat tserves tthe t end-user
trequirements tbest. tFor texample, ta tdesign tthat tworks twell tfor ta tmanufacturing tfirm tmay tnot tfit

tthe tneeds tof ta tmarketing tresearch tfirm, tand tvice tversa.




The tverification tprocess thelps tthe tdesigner tto tavoid timplementation tproblems tlater tby:

 Validating tthe tmodel's tentities. t(Remember tthe tminimal tdata trule.)
 Confirming tentity trelationships tand teliminating tduplicate, tunnecessary, tor
t improperlytdefined trelationships.

 Eliminating tdata tredundancies.
 Improving tthe tmodel's tsemantic tprecision tto tbetter trepresent treal-world toperations.
 Confirming tthat tall tuser trequirements t(processing, tperformance, tor tsecurity) tare tmet.


Verification tis ta tcontinuous tactivity tin tany tdatabase tdesign. tThe tdatabase tdesign tprocess tis
tevolutionary tin tnature: tIt trequires tthe tcontinuous tevaluation tof tthe tdeveloping tmodel tby

texamining tthe teffect tof tadding tnew tentities tand tby tconfirming tthat tany tdesign tchanges tenhance

tthe tmodel's taccuracy.




The tverification tprocess trequires tthe tfollowing tsteps:



1. Identify tthe tdatabase's tcentral tentity.


The t central t entity t is t the t most t important t entity t in t our t database, t and t most t of
t the t othertentities tdepend ton tit.




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, Appendix tC tThe tUniversity tLab:
Conceptual tDesign tVerification, tLogical tDesign, tand tImplementation


2. Identify tand tdefine teach tmodule tand tits tcomponents.


The t designer t divides t the t database t model t into t smaller t sets t that t reflect t the t data
t needs t oftparticular tsystems tmodules tsuch tas tinventory, torders, tpayroll, tetc.




3. Identify tand tdefine teach tof tthe tmodule's tprocesses.


Specifically, t this t step t requires t the t identification t and t definition t of t the t database t transactions
that trepresent tthe tmodule's treal-world toperations.




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