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What is a compound index? (Select one.)

An index that contains references to multiple fields within a document

✅

An index that supports queries that are run on two collections at the same time

An index that supports queries that combine the field name and the value into one string

An index that supports queries against unknown or arbitrary fields

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What is the maximum number of array fields per multikey index? (Select one.)

Unlimited

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To remove a database and all of its records from MongoDB, what operator should you use?:

Given a cursor named myCursor, pointing to the customers collection, how to you get basic info about it?:

What is the purpose of the $unwind stage in MongoDB aggregation framework?

To join data from multiple collections

To convert data into a graph

To store data in a flat file

To decompose an array into separate documents

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How can you update an array field by adding elements to it in MongoDB?

Using the $unset operator with the added elements.

Using the $addToSet operator with the new elements.

✅

Using the $push operator with the new elements.

Using the $set operator with the entire updated array.

❌

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What is the purpose of the $match stage in MongoDB aggregation framework?

To group data based on a specified expression

To filter documents based on a specified condition

✅

To rearrange documents based on a specified expression

To summarize data from multiple documents

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What

does the

$count stage return?

single document that contains the number of fields that have been modified in

an aggregation pipeline.

A single document with one field that contains

the value set to the number of documents at this stage in the aggregation

pipeline.

The

number of groups in an aggregation pipeline.

set number of documents from the aggregation pipeline.

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What is the

correct order of stages in the MongoDB aggregation pipeline when using both the

$match and $group stages?

The

order of the stages does not matter, and they can be used interchangeably.

$match

followed by $group

✅

$match

and $group cannot be used together in the same aggregation pipeline.

$group

followed by $match

The order

of the stages depends on the specific requirements of the aggregation query.

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What is the purpose of the $project stage in MongoDB aggregation framework?

To group data based on a specified expression

To filter documents based on a specified condition

To reshape documents by adding, removing, or modifying fields

✅

To summarize data from multiple documents

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