C100DEV by MongoDB Actual Free Exam Q&As

Question 1

Select all true statements about the $merge stage.

A. $merge stage allows us to output the documents to a collection in the same or different database. B. $merge stage allows us to output the documents to a sharded collection. C. $merge stage must be the last in the pipeline.

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Correct Answer: A,B,C Vote an answer

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Question 2

Select true statements about sorting & indexing performance.

A. Indexes can be traversed both forward and backward. B. Index prefixes cannot be used in query predicates to increase index utilization. C. It's possible to have a sorted query use an index for both sorting and filtering. D. Index prefixes can be used in sort predicates to prevent sort in memory.

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Correct Answer: A,C,D Vote an answer

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Question 3

Select all true statements about the $facet stage.

A. The $facet stage processes multiple aggregation pipelines within a single stage on the same set of input documents. B. The output of the $facet stage is subject to the 32 MB document size limit. If the results of the $facet stage exceed this limit, the aggregation produces an error. C. The output of the $facet stage is subject to the 16 MB document size limit. If the results of the $facet stage exceed this limit, the aggregation produces an error.

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Correct Answer: A,C Vote an answer

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Question 4

Select true statements regarding to MongoDB. Check all that apply.

A. Documents in MongoDB are organized into collections. B. MongoDB database organizes documents in rows and columns. C. MongoDB is a NoSQL database that uses documents to store data in an organized way.

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Correct Answer: A,C Vote an answer

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Question 5

We have a movies collection with the following document structure: { _id: ObjectId("573a1390f29313caabcd6223"), genres: [ 'Comedy', 'Drama', 'Family' ], title: 'The Poor Little Rich Girl', released: ISODate("1917-03-05T00:00:00.000Z"), year: 1917, imdb: { rating: 6.9, votes: 884, id: 8443 } }, { _id: ObjectId("573a13e3f29313caabdc08a4"), genres: [ 'Horror', 'Thriller' ], title: 'Mary Loss of Soul', year: 2014, imdb: { rating: '', votes: '', id: 2904798 } } We need to use Aggregation Framework to calculate the following aggregates: -> average imdb rating -> minimum imdb rating -> maximum imdb rating Expected output: [ { _id: null, avg_rating: 6.6934040649367255, min_rating: 1.6, max_rating: 9.6 } ] Please note that some documents have "" (empty string) for the field "imdb.rating". Exclude these documents before aggregation. Which pipeline should you use?

A. [{ $match: { "imdb.rating": { $ne: "" } } }, { $group: { _id: null, avg_rating: { $avg: "$imdb.rating" }, min_rating: { $min: "$imdb.rating" }, max_rating: { $max: "$imdb.rating" } } }] B. [{ $match: { "imdb.rating": { $ne: "" } } }, { $group: { _id: null, avg_rating: { $avg: "imdb.rating" }, min_rating: { $min: "imdb.rating" }, max_rating: { $max: "imdb.rating" } } }] C. [{ $group: { _id: null, avg_rating: { $avg: "$imdb.rating" }, min_rating: { $min: "$imdb.rating" }, max_rating: { $max: "$imdb.rating" } } }] D. [{ $match: { "imdb.rating": { $ne: "" } } }, { $group: { _id: null, avg_rating: { avg: "$imdb.rating" }, min_rating: { min: "$imdb.rating" }, max_rating: { max: "$imdb.rating" } } }]

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Correct Answer: A Vote an answer

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Question 6

How to connect to MongoDB with mongod to localhost running on port 27017?

A. mongo --host 127.0.0.1:27000 B. mongoconnect --host 127.0.0.1:27017 C. mongo --host 127.0.0.1:27017

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Correct Answer: C Vote an answer

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Question 7

Assign typical operational tasks to the Database Administrator.

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

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Correct Answer: A Vote an answer

Question 8

Select all options when you should deploy a MongoDB deployment with security enabled.

A. Deployment of the development environment. B. Deployment of the production environment. C. Deployment of the evaluation environment. D. Deployment of the staging environment.

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Correct Answer: A,B,C,D Vote an answer

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Question 9

Select all true statements about elections (replica set).

A. Nodes with a higher priority are more likely to be selected as primary node. B. Setting a node's priority to 0 ensures that a node never becomes primary. C. Not all nodes have equal chances to become the primary node. D. Elections can take place anytime while the primary is available.

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Correct Answer: A,B,C Vote an answer

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Question 10

What stages will cause a merge on the primary shard for a database?

A. $out B. $group C. $lookup

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Correct Answer: A,C Vote an answer

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Question 11

Select true statements about data modeling in MongoDB.

A. To avoid having to join data in the application layer from different collections you can denormalize your data. B. If one of your application's main queries is to retrieve related information from different collections, it is usually better to group that information into a single document. C. It's good data modeling practice to directly map each table from the relational model (normalized data) to the collection.

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Correct Answer: A,B Vote an answer

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MongoDB Certified Developer Associate - C100DEV Exam Practice Test