Free Access to MongoDB.C100DBA.v2024-07-08.q55 with Valid Practice Test (Page 8)

Question 31

You perform the following operation in the shell: db.foo.insert( { } ); What gets inserted?

A.No document will be inserted; an error will be raised
B.An empty document
C.A document will be inserted with the same _id as the last document inserted
D.A document with an _id assigned to be an Objectld
E.A document that matches the collection's existing schema, but with null fields

Question 32

Given a collection posts as shown below having a document array comments, which of the following command will create an index on the comment author descending?

A.db.posts.createIndex({comments.author":-l});
B.db.posts.createIndex({comments.$.author": {$desc:l>});
C.db.posts.createIndex({commerits.$.author":-l});

Question 33

Which of the following commands finds all the documents in the posts collection with post timestamp field as null?

A.db.posts.find( { post_timestamp: { $fieldtype: 10 } } )
B.db.posts.find( { post_timestamp: { $type: null } } )
C.db.posts.find( { post_timestamp: { $fieldtype: null } } )
D.db.posts.find( { post_timestamp : { $type; 10 > > )

Question 34

Which of the following is true about sharding?

A.Creating a sharded key automatically creates an index on the collection using that key
B.We cannot change a shard key directly/automatically once it is set up
C.A sharded environment does not support sorting functionality since the documents lie on various mongod instances
D.Sharding is enabled at the database level

Question 35

Which of the following is true about aggregation framework?

A.the aggregate command operates on a multiple collection
B.Pipeline expressions are stateless except accumulator expressions used with $group operator
C.Each aggregation operator need to return atleast one of more documents as a result
D.A single aggregation framework operator can be used more than once in a query

Question 31

Question 32

Question 33

Question 34

Question 35

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