MongoDB C100DEV 問題集

質問 1：
Which of the following actions are granted to the built-in readWrite role?
A. find
B. insert
C. remove
D. update
正解：A,B,C,D
解説: (Topexam メンバーにのみ表示されます)

質問 2：
The following capped collection is given: db.createCollection('latest_news', {'capped': true, 'size': 10000, 'max': 3}) [ { _id: ObjectId("61e8007c9b3067e362440a88"), title: 'COVID records broken again as weekend brings nearly 40K new cases' }, { _id: ObjectId("61e800989b3067e362440a89"), title: 'Bitcoin, Ethereum, Dogecoin Face Fresh Round Of Regulatory Scrutiny' }, { _id: ObjectId("61e800d19b3067e362440a8a"), title: 'Where Six Meme Stock Investors Are Now' } ] What the latest_news collection will look like after the following operation?
A. [ { _id: ObjectId("61e8007c9b3067e362440a88"), title: 'COVID records broken again as weekend brings nearly 40K new cases' }, { _id: ObjectId("61e800989b3067e362440a89"), title: 'Bitcoin, Ethereum, Dogecoin Face Fresh Round Of Regulatory Scrutiny' }, { _id: ObjectId("61e800d19b3067e362440a8a"), title: 'Where Six Meme Stock Investors Are Now' } ]
B. db.latest_news.insertOne({title: 'TikTok owner ByteDance dissolves its investment arm'}) [ { _id: ObjectId("61e800989b3067e362440a89"), title: 'Bitcoin, Ethereum, Dogecoin Face Fresh Round Of Regulatory Scrutiny' }, { _id: ObjectId("61e800d19b3067e362440a8a"), title: 'Where Six Meme Stock Investors Are Now' }, { _id: ObjectId("61e801439b3067e362440a8b"), title: 'TikTok owner ByteDance dissolves its investment arm' } ]
C. [ { _id: ObjectId("61e8007c9b3067e362440a88"), title: 'COVID records broken again as weekend brings nearly 40K new cases' }, { _id: ObjectId("61e800989b3067e362440a89"), title: 'Bitcoin, Ethereum, Dogecoin Face Fresh Round Of Regulatory Scrutiny' }, { _id: ObjectId("61e800d19b3067e362440a8a"), title: 'Where Six Meme Stock Investors Are Now' }, { _id: ObjectId("61e801439b3067e362440a8b"), title: 'TikTok owner ByteDance dissolves its investment arm' } ]
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 3：
There is a gamers collection in your database with the following document structure:
{ _id: 1, level: 15, is_active: true }, { _id: 2, level: 14, is_active: true }, { _id: 3, level: 7, is_active: false }
How do you update the value of the level field to 20 for a player with an id = 2?
Expected result:
{ _id: 1, level: 15, is_active: true }, { _id: 2, level: 20, is_active: true }, { _id: 3, level: 7, is_active: false }
A. db.gamers.update( { _id: 2 }, { $inc: { level: 20 } } )
B. db.gamers.update( { _id: 2 }, { $set: { level: 20 } } )
C. db.gamers.update( { _id: 2 }, { level: 20 } )
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 4：
We have an accounts collection with only one document: { _id: 54657, account_id: 557378, products: [ 'InvestmentStock', 'Commodity', 'CurrencyService' ] } We need to use Aggregation Framework to unwind the products Array to obtain new documents with only one product per document (see below). Expected output: [ { _id: 54657, account_id: 557378, products: 'InvestmentStock' }, { _id: 54657, account_id: 557378, products: 'Commodity' }, { _id: 54657, account_id: 557378, products: 'CurrencyService' } ] Which pipeline should you use?
A. [{ $project: { path: "$products", } }]
B. [{ $unset: { path: "$products", } }]
C. [{ $unwind: { path: "$products", } }]
D. [{ $facet: { path: "$products", } }]
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 5：
Suppose you have a following index for football_palyers collection: { "last_name": 1, "details.country": 1, "details.club": 1, "age": 1 } Determine which queries are able to successfully use a given index for both filtering and sorting.
A. db.football_players.find( { "last_name": "Lewandowski" } ).sort( { "details.country": 1, "details.club": 1 } )
B. db.football_players.find( { "last_name": { "$gte": "L" } } ).sort( { "details.club": -1 } )
C. db.football_players.find( { "last_name": "Lewandowski", "details.country": { "$gt": "D" } } ).sort( { "details.country": 1 } )
正解：A,C
解説: (Topexam メンバーにのみ表示されます)