Decision tables
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A decision table is used to represent the logic of making decisions in a tabular format. It contains conditions and actions. The document provides examples of creating decision tables for a login screen and photo upload screen. These tables contain conditions that must be met and the resulting actions. They can be used to systematically test all possible combinations of conditions.
Decision tables
- 1. DecisionTable A decisiontable isagraphical methodforexplainingthe logicof makingdecisionintabularformat. It isa setof conditions+setof actionsand differentcombinationsof decisions. “It isa matrix representationof logicof decisions whichspecifythe possible conditionsfordecisionand resultingactions.” The decisiontable isdividedintotwoparts: 1. Condition 2. Action 1. Condition: The conditionpartspecifiesall conditionsthatare appliedtothe inputteddata.Itis alsodividedinto twoparts à i. ConditionStub:- It describesthe conditionsthatexistinthe programlogic. ii. Condition Entry:- It providesanswerstoquestionsaskedinthe conditionaskedinthe conditionterm. 2. Action: The action part issubdividedintotwoparts à i. ActionStub:- It describesthe actiontobe takento meeteachcondition. ii. ActionEntry:- It describesthe appropriate actionresultingfromthe answertothe conditioninconditionentry. Format:
- 2. Table Heading DecisionRule ConditionStub ConditionEntry ActionStub ActionEntry Advantages of DecisionTable 1. It providescompactrepresentationof decisionmakingprocess. 2. It is easiertounderstandparticularpath. 3. It can be changedaccordingto situation. 4. These are bestsuitedforcalculatingdiscounts,commissionsorinventorycontrol procedures. 5. The structure of decisiontable promotesalogicallycomplete andconsistentproblemdefinition. Disadvantages of DecisionTable 1. It cannot expressthe completesequence of operationstosolve aproblemtherefore itmaybe difficultforthe programmertotranslate decisiontable intoprogram. 2. If there are too manyalternatives,itisdifficulttolistindecisiontable. 3. It doesnot showthe flowof logicfor the solutiontoa givenproblem. Let's create a decision table for a login screen. The conditionissimple if the userprovidescorrectusername andpasswordthe userwill be redirected to the homepage.If anyof the inputiswrong,an errormessage will be displayed. Conditions Rule 1 Rule 2 Rule 3 Rule 4 Username (T/F) F T F T Password (T/F) F F T T
- 3. Output (E/H) E E E H Legend: T – Correct username/password F – Wrong username/password E – Error message isdisplayed H – Home screenisdisplayed Interpretation: Case 1 – Username andpasswordbothwere wrong.The useris shownanerror message. Case 2 – Username wascorrect,but the passwordwaswrong.The useris shownanerror message. Case 3 – Username waswrong,but the passwordwascorrect.The useris shownanerror message. Case 4 – Username andpasswordbothwere correct,and the usernavigatedtohomepage While convertingthistotestcase,we can create 2 scenarios, Enter correctusername andcorrect password andclick onlogin,andthe expectedresultwill be the usershouldbe navigatedtohomepage Andone from the belowscenario Enter wrongusername andwrongpasswordandclickon login,andthe expectedresultwill be the usershouldgetan error message Enter correctusername andwrongpasswordand clickon login,andthe expectedresultwillbe the usershouldgetan error message Enter wrongusername andcorrectpasswordand clickon login,andthe expectedresultwillbe the usershouldgetan error message As theyessentiallytestthe same rule. Example 2: How to make DecisionTable for Upload Screen Nowconsidera dialogue box whichwill askthe usertouploadphotowithcertainconditionslike – 1. You can uploadonly'.jpg'formatimage
- 4. 2. file size lessthan32kb 3. resolution137*177. If any of the conditionsfailsthe systemwillthrow correspondingerrormessage statingthe issue andif all conditionsare metphotowill be updatedsuccessfully Let's create the decisiontable forthiscase. Conditions Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Case 7 Case 8 Format .jpg .jpg .jpg .jpg Not.jpg Not.jpg Not.jpg Not.jpg Size Lessthan 32kb Lessthan 32kb >= 32kb >= 32kb Lessthan 32kb Lessthan 32kb >= 32kb >= 32kb resolution 137*177 Not 137*177 137*177 Not 137*177 137*177 Not 137*177 137*177 Not 137*177 Output Photo uploaded Error message resolution mismatch Error message size mismatch Error message size and resolution mismatch Error message for format mismatch Error message formatand resolution mismatch Error message for format and size mismatch Error message for format, size,and resolution mismatch For thiscondition,we cancreate 8 differenttestcasesandensure completecoverage basedonthe above table. 1. Uploada photowithformat'.jpg', size lessthan32kb and resolution137*177 and clickon upload.ExpectedresultisPhotoshoulduploadsuccessfully 2. Uploada photowithformat'.jpg',size lessthan32kb and resolutionnot137*177 and clickon upload.ExpectedresultisError message resolutionmismatchshouldbe displayed 3. Uploada photowithformat'.jpg',size more than 32kb and resolution137*177 and clickon upload.ExpectedresultisError message size mismatchshouldbe displayed
- 5. 4. Uploada photowithformat'.jpg',size more than equal to32kb andresolutionnot137*177 and clickon upload.ExpectedresultisError message size andresolutionmismatchshouldbe displayed 5. Uploada photowithformatotherthan '.jpg',size lessthan32kb and resolution137*177 and clickon upload.ExpectedresultisError message forformatmismatchshouldbe displayed 6. Uploada photowithformatotherthan '.jpg',size lessthan32kb and resolutionnot137*177 and clickon upload.ExpectedresultisErrormessage formatand resolutionmismatchshould be displayed 7. Uploada photowithformatotherthan '.jpg',size more than32kb and resolution137*177 and clickon upload.ExpectedresultisError message forformatandsize mismatchshouldbe displayed 8. Uploada photowithformatotherthan '.jpg',size more than32kb and resolutionnot137*177 and clickon upload.ExpectedresultisErrormessage forformat,size andresolutionmismatch shouldbe displayed Q: An insurance companyusesthe followingrule todeterminethe eligibilityof adriverforinsurance. The driverwill be insuredif:- 1. The driverlivesinthe citywithpopulationlessthan5000 andhe ismarriedman. 2. The driverlivesinthe citywithpopulationlessthan5000 andhe ismarriedand age is over30 years old. 3. The driverlivesinthe citywithpopulationis5000 or more and it ismarriedfemale. 4. The driverismale over30. 5. The driverismarriedandunder30. Condition Rule1 Rule2 Rule3 Rule4 Rule5 Else Livesincity population<5000 Y Y N - - - Male Y - N Y - - Married Y Y Y - Y -
- 6. Q: Studyfollowingconditionsanddrawa decisiontable:- 1. If productcode=A Andcustomertype=1 Andthe order amount<=700 Then5% discountallowed 2. If productcode=A Andcustomertype=2 Andthe order amount<=700 Then7.5% discountallowed 3. If productcode=A Andcustomertype=1 Andthe order amount>=700 Then7.5% discountallowed 4. If productcode=A Andcustomertype=2 Age>30 - Y - Y N - Action Rule1 Rule2 Rule3 Rule4 Rule5 Else Insured Y Y Y Y Y Uninsured Y
- 7. Andthe order amount>700 Then10% discountallowed 5. A flatdiscountof 5% onproduct code=Bregardlessof customertype andthe orderamount Q: Draw a decision table fora company withthree person A,B,Cwhose share inthe companyare 50%,20%,30% sequentially.Anylow arisesinthe companywill be passedif itis supportedbyshare holdersandwhose share holdingexceed2/3of the total shares. Condition Rule1 Rule2 Else A 50% Y Y - B 20% N Y - C 30% Y N - Action Rule1 Rule2 Else Low Passed Y Y Condition Rule1 Rule2 Rule3 Rule4 Rule5 Else Product code=A Y Y Y Y N - Customer type=1 Y N Y N - - Order amount<=700 Y Y N N - - Action Rule1 Rule2 Rule3 Rule4 Rule5 Else Discount5% Y Y Discount 7.5% Y Y Discount10% Y No Discount Y
- 8. Low Rejected N Q: A Co-operatingbankxyzgrantedloanunderfollowingconditionsdraw decisiontableandtree- 1. If a customerhas a account withthe bankand has no loanoutstanding(nodues),loanwill be granted. 2. If a customerhas an account isoutstandingfrompreviousloan,loanwill be grantedif special managementapproval isobtained. 3. Rejectloanapplicationinall othercases. Condition Rule1 Rule2 Else CustomerhasAccount Y Y - No Out-standingloan amount Y N - Special ManagementApproval - Y - Action Rule1 Rule2 Else Loan ApplicationAccept Y Y Loan ApplicationReject