C100DEV 試験問題を無料オンラインアクセス

You want to execute the following query quite often in your application: db.hotels.aggregate([ { "$match": { "stars": { "$gt": 4.5 } } }, { "$sort": { "stars": 1 } } ]) Your collection doesn't have any additional indexes. Which index should you create to support this query?

• A.In this case, the index could not be created.
• B.db.hotels.createIndex( { "stars": 1 } )
• C.db.hotels.createIndex( { "match": 1 } )

Why is MongoDB using BSON instead of JSON to store data? Select all that apply.

• A.BSON simply means 'Binary JSON'.
• B.BSON supports more data types than JSON.
• C.BSON contains metadata to describe a document/object.
• D.BSON format is not human readable (BSON is machine-readable only).

Data modeling. You are considering the use of nesting or the references in your data model. Data read operations must be fast. Which option would be more appropriate?

• A.Use of nesting.
• B.Use of reference.

You are working in a team on a certain application in the gaming sector. Queries similar to the following are quite often executed by your application. db.gamers.find( { level: 10, is_active: true } ) How can you speed up the execution of similar queries? Choose the best option.

• A.db.gamers.createIndex( { level: 1 } )
• B.Create the given index:
• C.Create the given index:
• D.db.gamers.createIndex( { level: 1, is_active: 1 } )
• E.Create the given index:
• F.db.gamers.createIndex( { is_active: 1 } )
• G.There is no way to speed up this query.

Select true statements about data modeling in MongoDB.

• A.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.
• B.It's good data modeling practice to directly map each table from the relational model (normalized data) to the collection.
• C.To avoid having to join data in the application layer from different collections you can denormalize your data.