MongoDB MongoDB Certifications C100DBA Questions & Answers

• Question 111:

  Consider that you have a collection called population which has fields state and city. Which of the following query will calculate the population grouped by state and city?

  A. db.population.aggregate( [{ $group: { _id: { state: "$state", city; "$city" },pop: { $sum: 1 > > >] )

  B. db.population.aggregate( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $pop: 1 } } }] )

  C. db.population.aggregate( [{ $group: { _id: { state: Estate", city: n$city" },pop: { $sum: "$pop" } } }] )

  D. db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB

  Correct Answer: C

• Question 112:

  JSON stands for

  A. JavaScript Object Notation

  B. JavaScript Object Naming

  C. JavaScript Object Notice

  D. None of the above

  Correct Answer: A

• Question 113:

  What is the replication factor for a replicated cluster with 1 primary, 3 secondaries with one of them hidden.

  The set also has an arbiter?

  A. None of the above

  B. 5

  C. 3

  D. 4

  Correct Answer: D

• Question 114:

  Which of the documents below will be retrieved by the following query? Assume the documents are stored in a collection called "sample". Check all that apply.

  db.sample.find( { "$or" : [ { "a" : { "$in" : [ 3, 10] > }, { "b" : { "$lt" : 2 > > ] > )

  A. {''__id" :3, "a": 4, "c" :0, "b" :14}

  B. {''_Jd" :7, "a": 8, "c" :1, "b" :7}

  C. {".Jd" :6, "a": 1, "c" :1, "b" :5}

  D. { ''\Jd" :9, "a": 17, "c": 1, "b": 1}

  E. { \Jd" :10,"a": 3, "c": 1, "b": 1}

  F. {".Jd" :: 2, "a": 2, "c" :: 0, "b": 1}

  G. {".Jd" :: 4, "a": 5, "c" :: 0, "b": 17}

  H. {".Jd" :: 1, "a": 0, "c" :: 0, "b": 2}

  I. {".Jd" :: 5, "a": 3, "c" :: 0, "b": 12}

  J. {".Jd" :: 8, "a": 11, "c": 1, "b": 0}

  Correct Answer: DEFIJ

• Question 115:

  What is the first task that a secondary would perform on being prompted by another secondary for an election?

  A. Start the election process for primary

  B. Vote for the first secondary so that it would become the next primary

  C. Vote for itself and then call for election

  D. Connect to primary to confirm its availability

  Correct Answer: D

• Question 116:

  What read preference should your application use if you want to read from the primary under normal circumstances but allow reads from secondaries when a primary is unavailable?

  A. secondaryPreferred

  B. Secondary

  C. nearest

  D. primary

  E. primaryPreferred

  Correct Answer: E

• Question 117:

  Which of the following operators is used to updated a document partially?

  A. $set

  B. $update

  C. $project

  D. $modify

  Correct Answer: A

• Question 118:

  Which mongodb tool is used to report details on number of database operations in MongoDB?

  A. mongorestore

  B. mongostat

  C. mongodump

  D. mongotop

  Correct Answer: B

• Question 119:

  In a sharded replica set environment, the w Option provides ability for write concern and j Option provides

  ability for the data to be written on disk journal. Consider that we have a seven member replica set and we

  want to assure that the writes are committed to journal.

  What should be the value of j?

  A. 7

  B. 2

  C. 1

  D. 0

  Correct Answer: C

• Question 120:

  Which option should be used to update all the documents with the specified condition in the MongoDB query?

  A. specify {all: true} as the third parameter of update command

  B. updateAII instead of update

  C. specify {updateAII: true} as the third parameter of update command

  D. specify {multi : true} as the third parameter of update command

  Correct Answer: D