Quiz Databricks-Certified-Professional-Data-Engineer: Databricks Certified Data Engineer Professional
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Question: / 10
Quiz
Question 1/101/10
Toidentifythetopusersconsumingcomputeresources,adataengineeringteamneedstomonitor
usagewithintheirDatabricksworkspaceforbetterresourceutilizationandcostcontrol.Theteam
decidedtouseDatabrickssystemtables,availableunderthesystemcataloginUnityCatalog,togain
detailedvisibilityintoworkspaceactivity.WhichSQLqueryshouldtheteamrunfromthesystem
catalogtoachievethis?
usagewithintheirDatabricksworkspaceforbetterresourceutilizationandcostcontrol.Theteam
decidedtouseDatabrickssystemtables,availableunderthesystemcataloginUnityCatalog,togain
detailedvisibilityintoworkspaceactivity.WhichSQLqueryshouldtheteamrunfromthesystem
catalogtoachievethis?
Select the answer:Select the answer
1 correct answerA.
SELECT sku_name, identity_metadata.created_byASuser_email, SUM(usage_quantity*usage_unit)AStotal_dbus FROMsystem.billing.usage GROUPBYuser_email,sku_name ORDERBYtotal_dbusDESC LIMIT10
B.
SELECT sku_name, identity_metadata.created_byASuser_email, COUNT(usage_quantity)AStotal_dbus FROMsystem.billing.usage GROUPBYuser_email,sku_name [http://www.justcerts.com](http://www.justcerts.com) Questions&AnswersPDF P-212 ORDERBYtotal_dbusDESC LIMIT10
C.
SELECT identity_metadata.run_asASuser_email, SUM(usage_quantity)AStotal_dbus FROMsystem.billing.usage GROUPBYuser_email ORDERBYtotal_dbusDESC LIMIT10
D.
SELECT sku_name, usage_metadata.run_nameASuser_email, SUM(usage_quantity)AStotal_dbus FROMsystem.billing.usage GROUPBYuser_email,sku_name ORDERBYtotal_dbusDESC LIMIT10
Quiz
Question 2/102/10
AnupstreamsystemhasbeenconfiguredtopassthedateforagivenbatchofdatatotheDatabricks
JobsAPIasaparameter.Thenotebooktobescheduledwillusethisparametertoloaddatawiththe
followingcode:
df=spark.read.format("parquet").load(f"/mnt/source/(date)")
WhichcodeblockshouldbeusedtocreatethedatePythonvariableusedintheabovecodeblock?
A.date=spark.conf.get("date")
B.input_dict=input()date=input_dict["date"]
C.importsysdate=sys.argv[1]
D.date=dbutils.notebooks.getParam("date")
E.dbutils.widgets.text("date","null")date=dbutils.widgets.get("date")
JobsAPIasaparameter.Thenotebooktobescheduledwillusethisparametertoloaddatawiththe
followingcode:
df=spark.read.format("parquet").load(f"/mnt/source/(date)")
WhichcodeblockshouldbeusedtocreatethedatePythonvariableusedintheabovecodeblock?
A.date=spark.conf.get("date")
B.input_dict=input()date=input_dict["date"]
C.importsysdate=sys.argv[1]
D.date=dbutils.notebooks.getParam("date")
E.dbutils.widgets.text("date","null")date=dbutils.widgets.get("date")
Check the image below to see the right answer:Select the answer
1 correct answerThecodeblockthatshouldbeusedtocreatethedatePythonvariableusedintheabovecodeblock
is:
dbutils.widgets.text(“date”,“null”)date=dbutils.widgets.get(“date”)
Thiscodeblockusesthedbutils.widgetsAPItocreateandgetatextwidgetnamed“date”thatcan
acceptastringvalueasaparameter1.Thedefaultvalueofthewidgetis“null”,whichmeansthatif
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noparameterispassed,thedatevariablewillbe“null”.However,ifaparameterispassedthrough
theDatabricksJobsAPI,thedatevariablewillbeassignedthevalueoftheparameter.Forexample,if
theparameteris“2021-11-01”,thedatevariablewillbe“2021-11-01”.Thisway,thenotebookcan
usethedatevariabletoloaddatafromthespecifiedpath.
Theotheroptionsarenotcorrect,because:
OptionAisincorrectbecausespark.conf.get(“date”)isnotavalidwaytogetaparameterpassed
throughtheDatabricksJobsAPI. Thespark.confAPIisusedtogetorsetSparkconfiguration
properties,notnotebookparameters2.
OptionBisincorrectbecauseinput()isnotavalidwaytogetaparameterpassedthroughthe
DatabricksJobsAPI. Theinput()functionisusedtogetuserinputfromthestandardinputstream,
notfromtheAPIrequest3.
OptionCisincorrectbecausesys.argv1 isnotavalidwaytogetaparameterpassedthroughthe
DatabricksJobsAPI. Thesys.argvlistisusedtogetthecommand-lineargumentspassedtoaPython
script,nottoanotebook4.
OptionDisincorrectbecausedbutils.notebooks.getParam(“date”)isnotavalidwaytogeta
parameterpassedthroughtheDatabricksJobsAPI. Thedbutils.notebooksAPIisusedtogetorset
notebookparameterswhenrunninganotebookasajoborasasubnotebook,notwhenpassing
parametersthroughtheAPI5.
Reference: Widgets, SparkConfiguration, input(), sys.argv, Notebooks
is:
dbutils.widgets.text(“date”,“null”)date=dbutils.widgets.get(“date”)
Thiscodeblockusesthedbutils.widgetsAPItocreateandgetatextwidgetnamed“date”thatcan
acceptastringvalueasaparameter1.Thedefaultvalueofthewidgetis“null”,whichmeansthatif
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noparameterispassed,thedatevariablewillbe“null”.However,ifaparameterispassedthrough
theDatabricksJobsAPI,thedatevariablewillbeassignedthevalueoftheparameter.Forexample,if
theparameteris“2021-11-01”,thedatevariablewillbe“2021-11-01”.Thisway,thenotebookcan
usethedatevariabletoloaddatafromthespecifiedpath.
Theotheroptionsarenotcorrect,because:
OptionAisincorrectbecausespark.conf.get(“date”)isnotavalidwaytogetaparameterpassed
throughtheDatabricksJobsAPI. Thespark.confAPIisusedtogetorsetSparkconfiguration
properties,notnotebookparameters2.
OptionBisincorrectbecauseinput()isnotavalidwaytogetaparameterpassedthroughthe
DatabricksJobsAPI. Theinput()functionisusedtogetuserinputfromthestandardinputstream,
notfromtheAPIrequest3.
OptionCisincorrectbecausesys.argv1 isnotavalidwaytogetaparameterpassedthroughthe
DatabricksJobsAPI. Thesys.argvlistisusedtogetthecommand-lineargumentspassedtoaPython
script,nottoanotebook4.
OptionDisincorrectbecausedbutils.notebooks.getParam(“date”)isnotavalidwaytogeta
parameterpassedthroughtheDatabricksJobsAPI. Thedbutils.notebooksAPIisusedtogetorset
notebookparameterswhenrunninganotebookasajoborasasubnotebook,notwhenpassing
parametersthroughtheAPI5.
Reference: Widgets, SparkConfiguration, input(), sys.argv, Notebooks
Quiz
Question 3/103/10
TheDatabricksworkspaceadministratorhasconfiguredinteractiveclustersforeachofthedata
engineeringgroups.Tocontrolcosts,clustersaresettoterminateafter30minutesofinactivity.Each
usershouldbeabletoexecuteworkloadsagainsttheirassignedclustersatanytimeoftheday.
Assumingusershavebeenaddedtoaworkspacebutnotgrantedanypermissions,whichofthe
followingdescribestheminimalpermissionsauserwouldneedtostartandattachtoanalready
configuredcluster.
A."CanManage"privilegesontherequiredcluster
B.WorkspaceAdminprivileges,clustercreationallowed."CanAttachTo"privilegesontherequired
cluster
C.Clustercreationallowed."CanAttachTo"privilegesontherequiredcluster
D."CanRestart"privilegesontherequiredcluster
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E.Clustercreationallowed."CanRestart"privilegesontherequiredcluster
engineeringgroups.Tocontrolcosts,clustersaresettoterminateafter30minutesofinactivity.Each
usershouldbeabletoexecuteworkloadsagainsttheirassignedclustersatanytimeoftheday.
Assumingusershavebeenaddedtoaworkspacebutnotgrantedanypermissions,whichofthe
followingdescribestheminimalpermissionsauserwouldneedtostartandattachtoanalready
configuredcluster.
A."CanManage"privilegesontherequiredcluster
B.WorkspaceAdminprivileges,clustercreationallowed."CanAttachTo"privilegesontherequired
cluster
C.Clustercreationallowed."CanAttachTo"privilegesontherequiredcluster
D."CanRestart"privilegesontherequiredcluster
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Questions&AnswersPDF P-4
E.Clustercreationallowed."CanRestart"privilegesontherequiredcluster
Check the image below to see the right answer:Select the answer
1 correct answer[https://learn.microsoft.com/en-us/azure/databricks/security/auth-authz/access-control/cluster-acl](https://learn.microsoft.com/en-us/azure/databricks/security/auth-authz/access-control/cluster-acl)
[https://docs.databricks.com/en/security/auth-authz/access-control/cluster-acl.html](https://docs.databricks.com/en/security/auth-authz/access-control/cluster-acl.html)
[https://docs.databricks.com/en/security/auth-authz/access-control/cluster-acl.html](https://docs.databricks.com/en/security/auth-authz/access-control/cluster-acl.html)
Quiz
Question 4/104/10
WhenschedulingStructuredStreamingjobsforproduction,whichconfigurationautomatically
recoversfromqueryfailuresandkeepscostslow?
A.Cluster:NewJobCluster;Retries:Unlimited;MaximumConcurrentRuns:Unlimited
B.Cluster:NewJobCluster;Retries:None;MaximumConcurrentRuns:1
C.Cluster:ExistingAll-PurposeCluster;Retries:Unlimited;MaximumConcurrentRuns:1
D.Cluster:NewJobCluster;Retries:Unlimited;MaximumConcurrentRuns:1
E.Cluster:ExistingAll-PurposeCluster;Retries:None;MaximumConcurrentRuns:1
recoversfromqueryfailuresandkeepscostslow?
A.Cluster:NewJobCluster;Retries:Unlimited;MaximumConcurrentRuns:Unlimited
B.Cluster:NewJobCluster;Retries:None;MaximumConcurrentRuns:1
C.Cluster:ExistingAll-PurposeCluster;Retries:Unlimited;MaximumConcurrentRuns:1
D.Cluster:NewJobCluster;Retries:Unlimited;MaximumConcurrentRuns:1
E.Cluster:ExistingAll-PurposeCluster;Retries:None;MaximumConcurrentRuns:1
Check the image below to see the right answer:Select the answer
1 correct answerMaximumconcurrentruns:Setto1.Theremustbeonlyoneinstanceofeachqueryconcurrently
active.Retries:SettoUnlimited.[https://docs.databricks.com/en/structured-streaming/query-](https://docs.databricks.com/en/structured-streaming/query-)
recovery.html
active.Retries:SettoUnlimited.[https://docs.databricks.com/en/structured-streaming/query-](https://docs.databricks.com/en/structured-streaming/query-)
recovery.html
Quiz
Question 5/105/10
ThedataengineeringteamhasconfiguredaDatabricksSQLqueryandalerttomonitorthevaluesin
aDeltaLaketable.Therecent_sensor_recordingstablecontainsanidentifyingsensor_idalongside
thetimestampandtemperatureforthemostrecent5minutesofrecordings.
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Questions&AnswersPDF P-5
Thebelowqueryisusedtocreatethealert:
Thequeryissettorefresheachminuteandalwayscompletesinlessthan10seconds.Thealertisset
totriggerwhenmean(temperature)>120.Notificationsaretriggeredtobesentatmostevery1
minute.
Ifthisalertraisesnotificationsfor3consecutiveminutesandthenstops,whichstatementmustbe
true?
A.Thetotalaveragetemperatureacrossallsensorsexceeded120onthreeconsecutiveexecutionsof
thequery
B.Therecent_sensor_recordingstablewasunresponsiveforthreeconsecutiverunsofthequery
C.Thesourcequeryfailedtoupdateproperlyforthreeconsecutiveminutesandthenrestarted
D.Themaximumtemperaturerecordingforatleastonesensorexceeded120onthreeconsecutive
executionsofthequery
E.Theaveragetemperaturerecordingsforatleastonesensorexceeded120onthreeconsecutive
executionsofthequery
aDeltaLaketable.Therecent_sensor_recordingstablecontainsanidentifyingsensor_idalongside
thetimestampandtemperatureforthemostrecent5minutesofrecordings.
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Questions&AnswersPDF P-5
Thebelowqueryisusedtocreatethealert:
Thequeryissettorefresheachminuteandalwayscompletesinlessthan10seconds.Thealertisset
totriggerwhenmean(temperature)>120.Notificationsaretriggeredtobesentatmostevery1
minute.
Ifthisalertraisesnotificationsfor3consecutiveminutesandthenstops,whichstatementmustbe
true?
A.Thetotalaveragetemperatureacrossallsensorsexceeded120onthreeconsecutiveexecutionsof
thequery
B.Therecent_sensor_recordingstablewasunresponsiveforthreeconsecutiverunsofthequery
C.Thesourcequeryfailedtoupdateproperlyforthreeconsecutiveminutesandthenrestarted
D.Themaximumtemperaturerecordingforatleastonesensorexceeded120onthreeconsecutive
executionsofthequery
E.Theaveragetemperaturerecordingsforatleastonesensorexceeded120onthreeconsecutive
executionsofthequery
Check the image below to see the right answer:Select the answer
1 correct answerThisisthecorrectanswerbecausethequeryisusingaGROUPBYclauseonthesensor_idcolumn,
whichmeansitwillcalculatethemeantemperatureforeachsensorseparately.Thealertwilltrigger
whenthemeantemperatureforanysensorisgreaterthan120,whichmeansatleastonesensorhad
anaveragetemperatureabove120forthreeconsecutiveminutes.Thealertwillstopwhenthemean
temperatureforallsensorsdropsbelow120.VerifiedReference:[DatabricksCertifiedDataEngineer
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-6
Professional],under“SQLAnalytics”section;DatabricksDocumentation,under“Alerts”section.
whichmeansitwillcalculatethemeantemperatureforeachsensorseparately.Thealertwilltrigger
whenthemeantemperatureforanysensorisgreaterthan120,whichmeansatleastonesensorhad
anaveragetemperatureabove120forthreeconsecutiveminutes.Thealertwillstopwhenthemean
temperatureforallsensorsdropsbelow120.VerifiedReference:[DatabricksCertifiedDataEngineer
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-6
Professional],under“SQLAnalytics”section;DatabricksDocumentation,under“Alerts”section.
Quiz
Question 6/106/10
Ajuniordevelopercomplainsthatthecodeintheirnotebookisn'tproducingthecorrectresultsin
thedevelopmentenvironment.Asharedscreenshotrevealsthatwhilethey'reusinganotebook
versionedwithDatabricksRepos,they'reusingapersonalbranchthatcontainsoldlogic.Thedesired
branchnameddev-2.3.9isnotavailablefromthebranchselectiondropdown.
Whichapproachwillallowthisdevelopertoreviewthecurrentlogicforthisnotebook?
A.UseRepostomakeapullrequestusetheDatabricksRESTAPItoupdatethecurrentbranchto
dev-2.3.9
B.UseRepostopullchangesfromtheremoteGitrepositoryandselectthedev-2.3.9branch.
C.UseRepostocheckoutthedev-2.3.9branchandauto-resolveconflictswiththecurrentbranch
D.MergeallchangesbacktothemainbranchintheremoteGitrepositoryandclonetherepoagain
E.UseRepostomergethecurrentbranchandthedev-2.3.9branch,thenmakeapullrequesttosync
withtheremoterepository
thedevelopmentenvironment.Asharedscreenshotrevealsthatwhilethey'reusinganotebook
versionedwithDatabricksRepos,they'reusingapersonalbranchthatcontainsoldlogic.Thedesired
branchnameddev-2.3.9isnotavailablefromthebranchselectiondropdown.
Whichapproachwillallowthisdevelopertoreviewthecurrentlogicforthisnotebook?
A.UseRepostomakeapullrequestusetheDatabricksRESTAPItoupdatethecurrentbranchto
dev-2.3.9
B.UseRepostopullchangesfromtheremoteGitrepositoryandselectthedev-2.3.9branch.
C.UseRepostocheckoutthedev-2.3.9branchandauto-resolveconflictswiththecurrentbranch
D.MergeallchangesbacktothemainbranchintheremoteGitrepositoryandclonetherepoagain
E.UseRepostomergethecurrentbranchandthedev-2.3.9branch,thenmakeapullrequesttosync
withtheremoterepository
Check the image below to see the right answer:Select the answer
1 correct answerThisisthecorrectanswerbecauseitwillallowthedevelopertoupdatetheirlocalrepositorywith
thelatestchangesfromtheremoterepositoryandswitchtothedesiredbranch.Pullingchangeswill
notaffectthecurrentbranchorcreateanyconflicts,asitwillonlyfetchthechangesandnotmerge
them.Selectingthedev-2.3.9branchfromthedropdownwillcheckoutthatbranchanddisplayits
contentsinthenotebook.VerifiedReference:[DatabricksCertifiedDataEngineerProfessional],
under“DatabricksTooling”section;DatabricksDocumentation,under“Pullchangesfromaremote
repository”section.
thelatestchangesfromtheremoterepositoryandswitchtothedesiredbranch.Pullingchangeswill
notaffectthecurrentbranchorcreateanyconflicts,asitwillonlyfetchthechangesandnotmerge
them.Selectingthedev-2.3.9branchfromthedropdownwillcheckoutthatbranchanddisplayits
contentsinthenotebook.VerifiedReference:[DatabricksCertifiedDataEngineerProfessional],
under“DatabricksTooling”section;DatabricksDocumentation,under“Pullchangesfromaremote
repository”section.
Quiz
Question 7/107/10
ThesecurityteamisexploringwhetherornottheDatabrickssecretsmodulecanbeleveragedfor
connectingtoanexternaldatabase.
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-7
AftertestingthecodewithallPythonvariablesbeingdefinedwithstrings,theyuploadthepassword
tothesecretsmoduleandconfigurethecorrectpermissionsforthecurrentlyactiveuser.Theythen
modifytheircodetothefollowing(leavingallothervariablesunchanged).
Whichstatementdescribeswhatwillhappenwhentheabovecodeisexecuted?
A.Theconnectiontotheexternaltablewillfail;thestring"redacted"willbeprinted.
B.Aninteractiveinputboxwillappearinthenotebook;iftherightpasswordisprovided,the
connectionwillsucceedandtheencodedpasswordwillbesavedtoDBFS.
C.Aninteractiveinputboxwillappearinthenotebook;iftherightpasswordisprovided,the
connectionwillsucceedandthepasswordwillbeprintedinplaintext.
D.Theconnectiontotheexternaltablewillsucceed;thestringvalueofpasswordwillbeprintedin
plaintext.
E.Theconnectiontotheexternaltablewillsucceed;thestring"redacted"willbeprinted.
connectingtoanexternaldatabase.
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-7
AftertestingthecodewithallPythonvariablesbeingdefinedwithstrings,theyuploadthepassword
tothesecretsmoduleandconfigurethecorrectpermissionsforthecurrentlyactiveuser.Theythen
modifytheircodetothefollowing(leavingallothervariablesunchanged).
Whichstatementdescribeswhatwillhappenwhentheabovecodeisexecuted?
A.Theconnectiontotheexternaltablewillfail;thestring"redacted"willbeprinted.
B.Aninteractiveinputboxwillappearinthenotebook;iftherightpasswordisprovided,the
connectionwillsucceedandtheencodedpasswordwillbesavedtoDBFS.
C.Aninteractiveinputboxwillappearinthenotebook;iftherightpasswordisprovided,the
connectionwillsucceedandthepasswordwillbeprintedinplaintext.
D.Theconnectiontotheexternaltablewillsucceed;thestringvalueofpasswordwillbeprintedin
plaintext.
E.Theconnectiontotheexternaltablewillsucceed;thestring"redacted"willbeprinted.
Check the image below to see the right answer:Select the answer
1 correct answerThisisthecorrectanswerbecausethecodeisusingthedbutils.secrets.getmethodtoretrievethe
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-8
passwordfromthesecretsmoduleandstoreitinavariable.Thesecretsmoduleallowsusersto
securelystoreandaccesssensitiveinformationsuchaspasswords,tokens,orAPIkeys.The
connectiontotheexternaltablewillsucceedbecausethepasswordvariablewillcontaintheactual
passwordvalue.However,whenprintingthepasswordvariable,thestring“redacted”willbe
displayedinsteadoftheplaintextpassword,asasecuritymeasuretopreventexposingsensitive
informationinnotebooks.VerifiedReference:[DatabricksCertifiedDataEngineerProfessional],
under“SecurityandGovernance”section;DatabricksDocumentation,under“Secrets”section.
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-8
passwordfromthesecretsmoduleandstoreitinavariable.Thesecretsmoduleallowsusersto
securelystoreandaccesssensitiveinformationsuchaspasswords,tokens,orAPIkeys.The
connectiontotheexternaltablewillsucceedbecausethepasswordvariablewillcontaintheactual
passwordvalue.However,whenprintingthepasswordvariable,thestring“redacted”willbe
displayedinsteadoftheplaintextpassword,asasecuritymeasuretopreventexposingsensitive
informationinnotebooks.VerifiedReference:[DatabricksCertifiedDataEngineerProfessional],
under“SecurityandGovernance”section;DatabricksDocumentation,under“Secrets”section.
Quiz
Question 8/108/10
ThedatascienceteamhascreatedandloggedaproductionmodelusingMLflow.Thefollowingcode
correctlyimportsandappliestheproductionmodeltooutputthepredictionsasanewDataFrame
namedpredswiththeschema"customer_idLONG,predictionsDOUBLE,dateDATE".
ThedatascienceteamwouldlikepredictionssavedtoaDeltaLaketablewiththeabilitytocompare
allpredictionsacrosstime.Churnpredictionswillbemadeatmostonceperday.
Whichcodeblockaccomplishesthistaskwhileminimizingpotentialcomputecosts?
A.preds.write.mode("append").saveAsTable("churn_preds")
B.preds.write.format("delta").save("/preds/churn_preds")C)
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D)
E)
C.OptionA
D.OptionB
E.OptionC
F.OptionD
G.OptionE
correctlyimportsandappliestheproductionmodeltooutputthepredictionsasanewDataFrame
namedpredswiththeschema"customer_idLONG,predictionsDOUBLE,dateDATE".
ThedatascienceteamwouldlikepredictionssavedtoaDeltaLaketablewiththeabilitytocompare
allpredictionsacrosstime.Churnpredictionswillbemadeatmostonceperday.
Whichcodeblockaccomplishesthistaskwhileminimizingpotentialcomputecosts?
A.preds.write.mode("append").saveAsTable("churn_preds")
B.preds.write.format("delta").save("/preds/churn_preds")C)
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D)
E)
C.OptionA
D.OptionB
E.OptionC
F.OptionD
G.OptionE
Select the answer:Select the answer
1 correct answerA.
The correct answer is A.
Why A is correct
The team wants to save predictions to a Delta Lake table and compare all predictions over time. Since churn predictions are made at most once per day, the data volume is naturally small and the write pattern is simple: append new results each day.
Option A:
preds.write.mode("append").saveAsTable("churn_preds")
This is the best choice because:
1. It appends new daily predictions
- Each run adds a new batch of predictions without overwriting prior ones.
- This preserves historical data, which is necessary to compare predictions over time.
2. It stores the data as a table
- saveAsTable creates or writes to a managed table, which is convenient for analytics and querying.
3. It minimizes compute costs
- Since predictions are only produced once per day, there is no need for more complex transactional logic, partition management, or expensive rewrite operations.
- Append mode is efficient and avoids recomputing existing data.
Why the other options are not as good
Why A is correct
The team wants to save predictions to a Delta Lake table and compare all predictions over time. Since churn predictions are made at most once per day, the data volume is naturally small and the write pattern is simple: append new results each day.
Option A:
preds.write.mode("append").saveAsTable("churn_preds")
This is the best choice because:
1. It appends new daily predictions
- Each run adds a new batch of predictions without overwriting prior ones.
- This preserves historical data, which is necessary to compare predictions over time.
2. It stores the data as a table
- saveAsTable creates or writes to a managed table, which is convenient for analytics and querying.
3. It minimizes compute costs
- Since predictions are only produced once per day, there is no need for more complex transactional logic, partition management, or expensive rewrite operations.
- Append mode is efficient and avoids recomputing existing data.
Why the other options are not as good
B.
preds.write.format("delta").save("/preds/churn_preds")
- This saves Delta files to a path, but not necessarily as a table.
- While it can work for storage, it does not directly create a queryable table for easy comparison over time.
- It is also less aligned with the requirement than saving as a table.
Any option that overwrites data
- Would destroy historical predictions, making time-based comparison impossible.
Any option using merge/upsert or unnecessary repartitioning
- These are more computationally expensive than simply appending daily prediction results.
- Since the use case is one batch per day, append is sufficient and cheapest.
Key idea
To compare predictions across time, you must keep all past predictions. The simplest and most cost-effective way is to append each day’s prediction output into a Delta table.
Final answer: A
- This saves Delta files to a path, but not necessarily as a table.
- While it can work for storage, it does not directly create a queryable table for easy comparison over time.
- It is also less aligned with the requirement than saving as a table.
Any option that overwrites data
- Would destroy historical predictions, making time-based comparison impossible.
Any option using merge/upsert or unnecessary repartitioning
- These are more computationally expensive than simply appending daily prediction results.
- Since the use case is one batch per day, append is sufficient and cheapest.
Key idea
To compare predictions across time, you must keep all past predictions. The simplest and most cost-effective way is to append each day’s prediction output into a Delta table.
Final answer: A
Quiz
Question 9/109/10
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-10
AnupstreamsourcewritesParquetdataashourlybatchestodirectoriesnamedwiththecurrent
date.Anightlybatchjobrunsthefollowingcodetoingestalldatafromthepreviousdayasindicated
bythedatevariable:
Assumethatthefieldscustomer_idandorder_idserveasacompositekeytouniquelyidentifyeach
order.
Iftheupstreamsystemisknowntooccasionallyproduceduplicateentriesforasingleorderhours
apart,whichstatementiscorrect?
A.Eachwritetotheorderstablewillonlycontainuniquerecords,andonlythoserecordswithout
duplicatesinthetargettablewillbewritten.
B.Eachwritetotheorderstablewillonlycontainuniquerecords,butnewlywrittenrecordsmay
haveduplicatesalreadypresentinthetargettable.
C.Eachwritetotheorderstablewillonlycontainuniquerecords;ifexistingrecordswiththesame
keyarepresentinthetargettable,theserecordswillbeoverwritten.
D.Eachwritetotheorderstablewillonlycontainuniquerecords;ifexistingrecordswiththesame
keyarepresentinthetargettable,theoperationwilltail.
E.Eachwritetotheorderstablewillrundeduplicationovertheunionofnewandexistingrecords,
ensuringnoduplicaterecordsarepresent.
Questions&AnswersPDF P-10
AnupstreamsourcewritesParquetdataashourlybatchestodirectoriesnamedwiththecurrent
date.Anightlybatchjobrunsthefollowingcodetoingestalldatafromthepreviousdayasindicated
bythedatevariable:
Assumethatthefieldscustomer_idandorder_idserveasacompositekeytouniquelyidentifyeach
order.
Iftheupstreamsystemisknowntooccasionallyproduceduplicateentriesforasingleorderhours
apart,whichstatementiscorrect?
A.Eachwritetotheorderstablewillonlycontainuniquerecords,andonlythoserecordswithout
duplicatesinthetargettablewillbewritten.
B.Eachwritetotheorderstablewillonlycontainuniquerecords,butnewlywrittenrecordsmay
haveduplicatesalreadypresentinthetargettable.
C.Eachwritetotheorderstablewillonlycontainuniquerecords;ifexistingrecordswiththesame
keyarepresentinthetargettable,theserecordswillbeoverwritten.
D.Eachwritetotheorderstablewillonlycontainuniquerecords;ifexistingrecordswiththesame
keyarepresentinthetargettable,theoperationwilltail.
E.Eachwritetotheorderstablewillrundeduplicationovertheunionofnewandexistingrecords,
ensuringnoduplicaterecordsarepresent.
Check the image below to see the right answer:Select the answer
1 correct answer[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-11
ThisisthecorrectanswerbecausethecodeusesthedropDuplicatesmethodtoremoveany
duplicaterecordswithineachbatchofdatabeforewritingtotheorderstable.However,thismethod
doesnotcheckforduplicatesacrossdifferentbatchesorinthetargettable,soitispossiblethat
newlywrittenrecordsmayhaveduplicatesalreadypresentinthetargettable.Toavoidthis,abetter
approachwouldbetouseDeltaLakeandperformanupsertoperationusingmergeInto.Verified
Reference:[DatabricksCertifiedDataEngineerProfessional],under“DeltaLake”section;Databricks
Documentation,under“DROPDUPLICATES”section.
Questions&AnswersPDF P-11
ThisisthecorrectanswerbecausethecodeusesthedropDuplicatesmethodtoremoveany
duplicaterecordswithineachbatchofdatabeforewritingtotheorderstable.However,thismethod
doesnotcheckforduplicatesacrossdifferentbatchesorinthetargettable,soitispossiblethat
newlywrittenrecordsmayhaveduplicatesalreadypresentinthetargettable.Toavoidthis,abetter
approachwouldbetouseDeltaLakeandperformanupsertoperationusingmergeInto.Verified
Reference:[DatabricksCertifiedDataEngineerProfessional],under“DeltaLake”section;Databricks
Documentation,under“DROPDUPLICATES”section.
Quiz
Question 10/1010/10
Ajuniormemberofthedataengineeringteamisexploringthelanguageinteroperabilityof
Databricksnotebooks.Theintendedoutcomeofthebelowcodeistoregisteraviewofallsalesthat
occurredincountriesonthecontinentofAfricathatappearinthegeo_lookuptable.
Beforeexecutingthecode,runningSHOWTABLESonthecurrentdatabaseindicatesthedatabase
containsonlytwotables:geo_lookupandsales.
Whichstatementcorrectlydescribestheoutcomeofexecutingthesecommandcellsinorderinan
interactivenotebook?
A.Bothcommandswillsucceed.Executingshowtableswillshowthatcountriesatandsalesathave
beenregisteredasviews.
B.Cmd1willsucceed.Cmd2willsearchallaccessibledatabasesforatableorviewnamedcountries
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-12
af:ifthisentityexists,Cmd2willsucceed.
C.Cmd1willsucceedandCmd2willfail,countriesatwillbeaPythonvariablerepresentinga
PySparkDataFrame.
D.Bothcommandswillfail.Nonewvariables,tables,orviewswillbecreated.
E.Cmd1willsucceedandCmd2willfail,countriesatwillbeaPythonvariablecontainingalistof
strings.
Databricksnotebooks.Theintendedoutcomeofthebelowcodeistoregisteraviewofallsalesthat
occurredincountriesonthecontinentofAfricathatappearinthegeo_lookuptable.
Beforeexecutingthecode,runningSHOWTABLESonthecurrentdatabaseindicatesthedatabase
containsonlytwotables:geo_lookupandsales.
Whichstatementcorrectlydescribestheoutcomeofexecutingthesecommandcellsinorderinan
interactivenotebook?
A.Bothcommandswillsucceed.Executingshowtableswillshowthatcountriesatandsalesathave
beenregisteredasviews.
B.Cmd1willsucceed.Cmd2willsearchallaccessibledatabasesforatableorviewnamedcountries
[http://www.justcerts.com](http://www.justcerts.com)
Questions&AnswersPDF P-12
af:ifthisentityexists,Cmd2willsucceed.
C.Cmd1willsucceedandCmd2willfail,countriesatwillbeaPythonvariablerepresentinga
PySparkDataFrame.
D.Bothcommandswillfail.Nonewvariables,tables,orviewswillbecreated.
E.Cmd1willsucceedandCmd2willfail,countriesatwillbeaPythonvariablecontainingalistof
strings.
Check the image below to see the right answer:Select the answer
1 correct answerThisisthecorrectanswerbecauseCmd1iswritteninPythonandusesalistcomprehensionto
extractthecountrynamesfromthegeo_lookuptableandstoretheminaPythonvariablenamed
countriesaf.Thisvariablewillcontainalistofstrings,notaPySparkDataFrameoraSQLview.Cmd2
iswritteninSQLandtriestocreateaviewnamedsalesafbyselectingfromthesalestablewhere
cityisincountriesaf.However,thiscommandwillfailbecausecountriesafisnotavalidSQLentity
andcannotbeusedinaSQLquery.Tofixthis,abetterapproachwouldbetousespark.sql()to
executeaSQLqueryinPythonandpassthecountriesafvariableasaparameter.VerifiedReference:
[DatabricksCertifiedDataEngineerProfessional],under“LanguageInteroperability”section;
DatabricksDocumentation,under“Mixlanguages”section.
extractthecountrynamesfromthegeo_lookuptableandstoretheminaPythonvariablenamed
countriesaf.Thisvariablewillcontainalistofstrings,notaPySparkDataFrameoraSQLview.Cmd2
iswritteninSQLandtriestocreateaviewnamedsalesafbyselectingfromthesalestablewhere
cityisincountriesaf.However,thiscommandwillfailbecausecountriesafisnotavalidSQLentity
andcannotbeusedinaSQLquery.Tofixthis,abetterapproachwouldbetousespark.sql()to
executeaSQLqueryinPythonandpassthecountriesafvariableasaparameter.VerifiedReference:
[DatabricksCertifiedDataEngineerProfessional],under“LanguageInteroperability”section;
DatabricksDocumentation,under“Mixlanguages”section.
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