MongoDB MongoDB Certifications C100DBA Questions & Answers

• Question 91:

  In a replica set, a_________number of members ensures that the replica set is always able to select a primary.

  A. Even

  B. Odd

  C. 2

  D. Depends on the application architecture

  Correct Answer: B

• Question 92:

  Which of the following node is used during election in a replication cluster?

  A. primary

  B. arbiter

  C. hidden

  D. secondary

  Correct Answer: B

• Question 93:

  You have designed a web application with mongoDB. You have configured replication. The replica set is in place and function properly. What happens in case of failure?

  A. Switchover needs to be done manually

  B. Failover happens automatically

  C. Switchover happens automatically

  D. Failover needs to be done manually

  Correct Answer: B

• Question 94:

  MongoDB is

  A. None of the above

  B. Object-oriented DBMS

  C. Relational DBMS

  D. Document-oriented DBMS

  Correct Answer: D

• Question 95:

  Which are the ONLY ways to project portions of an array?

  A. $slice

  B. $

  C. All of the above

  D. $ elemMatch

  Correct Answer: C

• Question 96:

  In a replicated cluster, which of the following node would only be used during an election?

  A. arbiter

  B. primary

  C. hidden

  D. secondary

  Correct Answer: A

• Question 97:

  Dada una coleccion, cuales devuelve con la siguiente query db.coleccion.find ({nombre:"ruben",apellido:"gomez"},{nombre:l,apellido:l,aficion:l});

  A. { "-id" : Objectld("580a42b5dfblb5al7427d302"), "nombre" : "ruben", "apellido" : "gomez", "aficion" : v u "flipar" }

  B. { "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "Luis", "apellido" : "gomez", "aficion" : u "flipar" }

  C. { "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "Pablo" , "aficion" : u "flipar"}

  D. { "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "gomez" >

  Correct Answer: AD

• Question 98:

  Which option can be used with update command so that a new document gets created if no matching document is found based on the query condition?

  A. upsert command instead of update command

  B. {update: true, insert: true} as the third parameter of update command

  C. This has to be handled in application code (Node.js, PHP, JAVA, C#, etc.) and cannot be handled in mongo shell query

  D. Specify {upsert : true } as the third parameter of update command

  Correct Answer: D

• Question 99:

  What does the totalKeysExamined field returned by the explain method indicate?

  A. Number of documents that match the query condition

  B. Number of index entries scanned

  C. Details the completed execution of the winning plan as a tree of stages

  D. Number of documents scanned

  Correct Answer: B

• Question 100:

  In order to ensure that you can maintain high availability in the face of server failure, you should implement which of the following?

  A. Sharding

  B. Properly defined user roles

  C. Replication

  D. Put indexes on all of your documents

  E. The proper storage engine

  Correct Answer: C