C100DBA Online Practice Questions and Answers

The MongoDB explain() method does not support which of the following verbosity mode:

A. executionStats

B. queryPlanner

C. customExecutionStats

D. allPlansExecution

JSON stands for

A. JavaScript Object Notation

B. JavaScript Object Naming

C. JavaScript Object Notice

D. None of the above

Which of the following is a valid Replica Set configuration if you want: 1-Have 3 copies of everything

2- That RS3 is never primary

2- That RSI and RS2 can be primary?

You had to see the different configurations, RS3 could be hidden or priority 0 (But not a referee because we need 3 replicas), while RSI and RS2 could NOT have priority 0 or be hidden or anything like that In a 4member RS RSO , RSI, RS2 and RS3 + Referee, RSO (primary) falls after some write operations that have replicated RSI and RS2 (but NOT RS3), who can get up as the new primary?

The configuration comes and in it we see that RS2 has a hidden: true (or a priority: 0, (I don't remember)

A. ORS1

B. ORS2

C. ORS3

D. O arbiter

E. RSO

Given a replica set with five data-bearing members, suppose the primary goes down with operations in its oplog that have been copied from the primary to only one secondary. Assuming no other problems occur, which of the following describes what is most likely to happen?

A. missing operations will need to be manually re-performed

B. the secondary with the most current oplog will be elected primary

C. reads will be stale until the primary comes back up

D. the primary may roll back the operations once it recovers

E. the most current secondary will roll back the operations following the election

What is the use of mongodump and mongorestore tools?

A. backup mongodb deployment

B. audit mongodb deployment

C. performance tune mongodb deployment

D. replicate mongodb deployments

Which of the following command is used to get all the indexes on a collection?

A. db.collection.showIndexes()

B. db.collection.findlndexes()

C. db.showIndexes()

D. db.collection.getlndexesQ

Which of the following is incorrect statement about find and findOne operations in MongoDB?

A. findQ returns all the documents in a collection while findOne() retrieves only the first one.

B. find.limit(l) is not the same query as findOne()

C. findOneQ returns the actual first document retrieved from a collection

D. findQ and findOneQ returns cursors to the collection documents

Consider the following example document from the sample collection. All documents in this collection have the same schema.

Which of the following queries will replace this with the document.

A. db.sample.update( { "_id" : 3 } , { "$set" : { "_id" : 7 , "c" : 4 > > )

B. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 > , { "justOne" : true > ) / This operation cannot be done with a single query.

C. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 , { "$unset" : [ "a" , "b" ] } } )

D. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 > )

Which command is used to determine storage capacity of specific database?

A. mongotop

B. dbstats

C. mongostat

D. constats

Which type of indexes does MongoDB support?

A. All of the above

B. Compound Indexes

C. Multikey Indexes

D. Geospatial Indexes