Given a companies collection where each document has the following structure:
{ _id: ObjectId('61a8b90c6d5ce6a7d8fef95e'), name: 'Facebook', tag_list: ['facebook', 'college', 'students', 'network'], description: 'Social network' }
Which of the following commands will add new fields to the updated documents?

• A.db.companies.updateMany({ "name": "Facebook" }, { "$push": { "tag_list": "media" } })
• B.db.companies.updateMany({ "name": "Facebook" }, { "$set": { "description": "Social media" } })
• C.db.companies.updateMany({ "name": "Facebook" }, { "$set": { "country": "USA" } })

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Suppose you have a developers collection with only two documents:
{ _id: 1, lname: 'Smith', tech_stack: [ 'sql', 'git', 'python', 'django' ], fname: 'Bob' }, { _id: 2, fname: 'Michael', lname: 'Doe', tech_stack: [ 'git', 'python', 'sqlite', 'linux', 'flask' ] }
Using Aggregation Framework you run the following stage:
{ $unwind: { path: '$tech_stack' } }
How many documents will you have in the pipeline after the $unwind stage?

• A.9
• B.2
• C.7
• D.5
• E.4

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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.

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The greater the cardinality of a field, the...

• A.less useful an index created on this field will be.
• B.more useful an index created on this field will be.

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Consider a one-to-one relationship observed between users and the users details. Basic information about application users is separated from detailed information. Which of the following are true about modeling this one-to-one relationship with the document model in MongoDB?

• A.We can embed fields with detailed information as a subdocument in the users collection.
• B.We can embed fields with detailed information in the users collection.
• C.We can link to a single document with detailed information in another collection.

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