MongoDB Exam C100DBA Topic 1 Question 64 Discussion

Actual exam question for MongoDB's C100DBA exam

Question #: 64
Topic #: 1

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?

Adb.posts.createIndex({^comments.$.author':-l});

Bdb. posts.createIndex({^comments.author' :1});

Cdb.posts.createIndex({^commerits.author';-!});

Show Suggested Answer

Suggested Answer: A, B, C

by Carmela at Jan 06, 2023, 07:14 AM

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Cora

13 days ago

I'm going with B. db.posts.createIndex({\'comments.author\':1}). It's the only one that looks like it actually creates an index on the 'comments' subdocument. The others seem a bit... creative.

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Gerardo

14 days ago

Hmm, this one's tricky. Is the answer B? db.posts.createIndex({\'comments.author\':1})? I hope I'm not just making a comment on the wrong post!

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Lashawn

17 days ago

I'm pretty sure the correct answer is C. db.posts.createIndex({\'^commerits.author\':-1}). Oops, my bad, I misspelled 'comments'!

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Rosalyn

2 months ago

I think the answer is A. db.posts.createIndex({\'^comments.$.author\':-1}). It seems to create an index on the 'author' field of the 'comments' subdocument in descending order.

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Monroe

28 days ago

User2: I think it might be B) db. posts.createIndex({^comments.author\' :1}).

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Tricia

1 months ago

User1: I agree with you, A) db.posts.createIndex({^comments.$.author\':-1}) looks like the correct command.

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Susana

2 months ago

I'm not sure, but I think option A might be correct as it mentions creating an index on comment author in descending order.

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2 months ago

I think the correct command is B) db.posts.createIndex({^comments.author :1});

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