C100DBA Online Practice Questions and Answers

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

A. $set

B. $update

C. $project

D. $modify

`$set' sets the value of

A. Code block

B. Name/value pair

C. Key

D. None of the above

You perform the following query on the sayings collection, which has the index { quote : "text" }: Assuming the documents below are in the collection, which ones will the following query return? Check all

that apply.

A. db.sayings.find( { $text : { $search : "fact find" } } )

B. { _id : 3, quote : "Nobody will ever catch me." }

C. { _id : 1, quote : "That's a fact, Jack." }

D. { _id : 2, quote : "Find out if that fact is correct." }

Which of the following aggregation commands in MongoDB does not support sharded collections?

A. mapReduce

B. group

C. aggregate

D. All of the above

Which mongodb tools allow us to work with our data in a human readable format?

A. mongodump

B. mongostat

C. mongoimport

D. mongoexport

Aggregation Pipelines have a limit of:

A. No limit on document and 100 MB RAM

B. 2 MB document and no limit on RAM

C. 2 MB document and 100 MB RAM

D. 16 MB document and 100 MB RAM

Consider the following example document:

{

"_id": Objectld("5360c0a0a655a60674680bbe"),

"user"

"login": "irOn"

"description": "Made of steel"

"date": ISODate("2014-04-30T09:16:45.836Z"),

}

>

and index creation command:

db.users.createlndex( { "user.login": 1, "user.date": -1 }, "mylndex" )

When performing the following query:

db.users.find( { "user.login": /Air.*/ },

{ "user":1, "_id":0 > ).sort( { "user.date":1 > )

which of the following statements correctly describe how MongoDB will handle the query? Check all that apply.

A. As an optimized sort query (scanAndOrder = false) using "mylndex" because we are sorting on an indexed field

B. As an indexed query using "mylndex" because field "user.login" is indexed

C. MongoDB will need to do a table/collection scan to find matching documents

D. None of the above

E. As a covered query using "mylndex" because we are filtering out "_id" and only returning "user.login"

Which of the following about Capped Collections is correct?

A. Fixed Size

B. Only "Fixed Size" and "High-throughput operations that insert and retrieve documents based on insertion order"

C. High-throughput operations that insert and retrieve documents based on insertion order

D. If the allocated space for a capped collection exceeds, it stops inserting new documents

Which of the following commands can cause the database to be locked?

A. All of the above

B. Inserting data

C. Map-reduce

D. Issuing a query

Update If Correct is an approach for which of the following concepts in MongoDB:

A. Concurrency Control

B. Atomicity

C. Performance Management

D. Transaction Management