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Question 31 Selectable Answer

Where is collection metadata stored in a sharded cluster?

A. In a random shard.
B. On the configuration servers.
C. In the primary shard.

Answer:
Explanation:
https://docs.mongodb.com/manual/sharding/

Question 32 Selectable Answer

We have the following indexes:
{ name: 1, founded_year: 1 }
{ tag_list: 1, is_active: 1 } And the following documents:
{
_id: ObjectId("52cdef7c4bab8bd675297daa"),
name: "Sparter",
founded_year: 2007,
tag_list: ["gaming", "game", "wow"],
is_active: true
},
{
_id: ObjectId("52cdef7c4bab8bd675297da3"),
name: "Yahoo!",
founded_year: 1994,
tag_list: ["search", "webmail"],
is_active: true
}
Select true statement.

A. There would be a total of 7 index keys created across all of these documents and indexes.
B. There would be a total of 4 index keys created across all of these documents and indexes.
C. There would be a total of 2 index keys created across all of these documents and indexes.

Answer:
Explanation:
https://docs.mongodb.com/manual/core/index-multikey/

Question 33 Selectable Answer

Use case: e-learning platform
Which of the following scenarios is the best candidate to use the Extended Reference Pattern to avoid additional reads by joins/lookups?

A. A course model needs to store references to image of the course that are kept in an external location outside the database.
B. Our app needs to retrieve a course and information about its instructor.
C. Our app needs to retrieve a course and its ten most recent reviews.
D. A course model needs to store a counter representing the number of times it was purchased.

Answer:
Explanation:
https://www.mongodb.com/blog/post/building-with-patterns-the-extended-reference-pattern

Question 34 Selectable Answer

You have the following replica set configuration:
conf = {
"_id": "replset",
"version": 1,
"protocolVersion": 1,
"members": [
{
"_id": 0,
"host": "192.168.120.24:27017",
"priority": 2,
"votes": 1
},
{
"_id": 1,
"host": "192.168.120.24:27018",
"priority": 1,
"votes": 1
},
{
"_id": 2,
"host": "192.168.120.24:27018",
"priority": 1,
"votes": 1
}
]
}
Select all true statements about this configuration.

A. This configuration is incorrect. You can only specify a priority of 0 or 1.
B. This configuration is incorrect. Host information must be unique for each member in a replica set.
C. This configuration is incorrect. Replica set cannot have three members.
D. This configuration is correct.

Answer:
Explanation:
https://docs.mongodb.com/manual/replication/#replication

Question 35 Selectable Answer

How can we represent a one-to-one relationship in MongoDB?

A. We can link to a single document in another collection.
B. We can embed fields as a child document in the document.
C. We can embed fields in the document.

Answer:
Explanation:
https://docs.mongodb.com/manual/tutorial/model-embedded-one-to-one-relationships-between-documen ts/

Question 36 Selectable Answer

MongoDB can benefit from adding more RAM to your servers.

A. No
B. Yes

Answer:

Question 37 Selectable Answer

In which of the following CRUD operations can you specify a write concern? Select all that apply.

A. db.collection.update()
B. db.collection.find()
C. db.collection.insert()
D. db.collection.updateMany()
E. db.collection.insertOne()

Answer:
Explanation:
https://docs.mongodb.com/manual/reference/write-concern/

Question 38 Selectable Answer

Complete the sentence below.

A. By default, all MongoDB user-created collections...
B. have an field_id index.
C. have an _id index.
D. have no index.

Answer:
Explanation:
https://docs.mongodb.com/manual/core/document/ https://docs.mongodb.com/manual/reference/method/ObjectId/

Question 39 Selectable Answer

Given a movies collection where each document has the following structure:
{
_id: ObjectId("573a1390f29313caabcd60e4"),
genres: [ 'Short', 'Comedy', 'Drama' ],
title: 'The Immigrant',
year: 1917,
imdb: { rating: 7.8, votes: 4680, id: 8133 },
countries: [ 'USA' ]
}
Which of the following queries will find all movies that do not contain the Comedy and Romance genres?

A. db.movies.find( { genres: { $or: ["Comedy", "Romance"] } } )
B. db.movies.find( { genres: { $in: ["Comedy", "Romance"] } } )
C. db.movies.find( { genres: { $nin: ["Comedy", "Romance"] } } )

Answer:
Explanation:
https://docs.mongodb.com/manual/reference/operator/query/nin/

Question 40 Selectable Answer

Given a movies collection where each document has the following structure:
{
_id: ObjectId('573a1390f29313caabcd60e4'),
genres: [ 'Short', 'Comedy', 'Drama' ],
title: 'The Immigrant',
year: 1917,
imdb: { rating: 7.8, votes: 4680, id: 8133 },
countries: [ 'USA' ]
}
Which of the following queries will find all movies that were made in 2000 or 2010?

A. db.movies.find( { $or: [ { year: 2000 }, { year: 2010 } ] } )
B. db.movies.find( { year: 2000, year: 2010 } )
C. db.movies.find( { $and: [ { year: 2000 }, { year: 2010 } ] } )
D. db.movies.find( { $in: [ { year: 2000 }, { year: 2010 } ] } )

Answer:
Explanation:
https://docs.mongodb.com/manual/reference/method/db.collection.find/ https://docs.mongodb.com/manual/reference/operator/query/or/

Question 41 Selectable Answer

Select scenarios that are best suited for applying the Schema Versioning Pattern.

A. Your team was assigned to update the current schema with additional fields without shutting down the system for this upgrade. However, all documents need to be quickly updated.
B. There is a requirement to keep multiple versions of a document, and those versions can have different fields for each version in your application.

Answer:
Explanation:
https://www.mongodb.com/blog/post/building-with-patterns-the-schema-versioning-pattern

Question 42 Selectable Answer

Does MongoDB support query operations that perform a text search of string content?

A. Yes
B. No

Answer:
Explanation:
https://docs.mongodb.com/manual/text-search/

Question 43 Selectable Answer

Assign typical operational tasks to the Data Scientist.

A. read data
B. write data
C. write data, read data
D. create user, create index

Answer:

Question 44 Selectable Answer

Suppose we have a shipwrecks collection with the following document structure:
{
_id: ObjectId("578f6fa2df35c7fbdbaed8ce"),
feature_type: 'Wrecks - Visible',
watlev: 'always dry',
coordinates: [ -79.9469681, 9.3729954 ]
}
You ran the command below:
db.shipwrecks.getIndexes()
And you got the following output:
[
{ v: 2, key: { _id: 1 }, name: '_id_' },
{
v: 2,
key: { coordinates: '2dsphere' },
name: 'coordinates_2dsphere',
'2dsphereIndexVersion': 3
}
]
How can you remove the geospatial index on the coordinates field?

A. db.shipwrecks.dropCollection('coordinates_2dsphere')
B. db.shipwrecks.dropIndex('coordinates_2dsphere')
C. db.shipwrecks.dropIndex('_id_')

Answer:
Explanation:
https://docs.mongodb.com/manual/core/2dsphere/

Question 45 Selectable Answer

Given a movies collection where each document has the following structure:
{
_id: ObjectId('573a1390f29313caabcd60e4'),
genres: [ 'Short', 'Comedy', 'Drama' ],
title: 'The Immigrant',
year: 1917,
imdb: { rating: 7.8, votes: 4680, id: 8133 },
countries: [ 'USA' ]
}
Which of the following queries will find all the movies that have more votes than the year in which they were released?

A. db.movies.find({ $expr: { $gt: ["imdb.votes", "year"] } } )
B. db.movies.find({ $expr: { $lt: ["$imdb.votes", "$year"] } } )
C. db.movies.find({ $expr: { $gt: ["$imdb.votes", "$year"] } } )

Answer:
Explanation:
https://docs.mongodb.com/manual/reference/method/db.collection.find/

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