MongoDB MongoDB Certifications C100DBA Questions & Answers

• Question 121:

  Given a collection posts as shown below having a document array comments, which of the following command will create an index on the comment author descending?

  

  A. db.posts.createIndex({commerits.$.author":-l});

  B. db.posts.createIndex({comments.$.author": {$desc:l>});

  C. db.posts.createIndex({comments.author":-l});

  Correct Answer: C

• Question 122:

  What is the maximum size of a MongoDB document?

  A. 2 MB

  B. 12 MB

  C. There is no maximum size. It depends on the RAM.

  D. 16 MB

  Correct Answer: D

• Question 123:

  If the value of totalKeysExamined is 30000 and the value of totalDocsExamined is 0, which of the following option is correct?

  A. None of the above

  B. The query used an index to fetch the results

  C. The query returned 0 documents

  D. The query returned 30000 documents after scanning the documents

  Correct Answer: B

• Question 124:

  Aggregation Pipelines have a limit of:

  A. 2 MB document and 100 MB RAM

  B. 16 MB document and 100 MB RAM

  C. No limit on document and 100 MB RAM

  D. 2 MB document and no limit on RAM

  Correct Answer: B

• Question 125:

  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. 1

  B. 2

  C. 0

  D. 7

  Correct Answer: B

• Question 126:

  Which of the following is supported by MongoDB?

  A. Transaction Management

  B. ACID Transactions

  C. Journaling

  D. Relationships between Collections (Primary Key Foreign Key)

  Correct Answer: C

• Question 127:

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

  A. executionStats

  B. queryPlanner

  C. customExecutionStats

  D. allPlansExecution

  Correct Answer: A

• Question 128:

  Consider a collection posts which has fields: Jd, post_text, post_author, post_timestamp, post_tags etc. Which of the following query retrieves ONLY the key named post_text from the first document retrieved?

  A. db.posts.finOne({},{_id:0, post_text:1})

  B. db.posts.findOne({post_text: 1})

  C. db.posts.find({},{_id:Of post_text:1})

  D. db.posts.finOne珆,{post_text:l})

  Correct Answer: A

• Question 129:

  What tool do you use to see if you have a problem in the consumption of disk I / 0?

  A. Mongoperf

  Correct Answer: A

• Question 130:

  In a collection that contains 100 post documents, what does the following command do? db. posts. find ().skip(5).limit(5)

  A. Skip and limit nullify each other. Hence returning the first five documents.

  B. Skips the first five documents and returns the next five

  C. Limits the first five documents and then return them in reverse order

  D. Skips the first five documents and returns the sixth document five times

  Correct Answer: B