2025年最新のC100DBA問題集レビュー専門クイズ学習材料 [Q30-Q53]

2025年最新のC100DBA問題集レビュー専門クイズ学習材料

C100DBAテスト準備トレーニング練習試験問題練習テスト

質問 # 30
JSON stands for

A. JavaScript Object Notice
B. JavaScript Object Naming
C. JavaScript Object Notation
D. None of the above

正解：C

質問 # 31
In a sharded replicas set environment with multiple mongos servers, which of the following would decide the mongos failover?

A. mongod
B. mongos
C. mongo shell
D. individual language drivers

正解：D

質問 # 32
What does the following aggregate query perform?

A. Fetches the posts with likes between 100 and 200 and sets their _id as null
B. Fetches the posts with likes between 100 and 200, sets the _id of the first document as null and then increments it 1 every time
C. Calculates the number of posts with likes between 100 and 200
D. Groups the posts by number of likes (101, 102, 103.) by adding 1 every time

正解：C

質問 # 33
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.$.author": {$desc:l>});
B. db.posts.createIndex({commerits.$.author":-l});
C. db.posts.createIndex({comments.author":-l});

正解：C

質問 # 34
Consider the following posts document:

Which of the following queries will return the documents but with only the first two tags in the tags array?

A. db.posts.find({author:"Tom"}.limit({tags:2})
B. Both "db.posts.find({author:"Tom"},{tags:{$slice:2}})" and
"db.posts.find({author:"Tom"}).limit($slice: {tags:2})" are valid. $slice works both with projection and limit.
C. db.posts.find({author:"Tom"}.limit($slice:{tags:2>)
D. db.posts.find({author:"Tom">,{tags:{$slice:2})

正解：D

質問 # 35
Mongodb does provide high availability via which option?

A. Replication
B. Indexing
C. Journaling
D. Sharding

正解：A

質問 # 36
The difference between $push and $addToSet is:

A. $addToSet needs the fields to be already present while $push will work even if the field is not present
B. $addToSet adds the item to the field only if the new item is of the same datatype
C. There is no major difference between them. $addToSet is a deprecated version of $push.
D. $addToSet adds the item to the field only if it does not exist already; while $push pushes the item to the field irrespective of whether it was present or not

正解：D

質問 # 37
What does the output x of the following MongoDB aggregation query result into; db.posts.aggregate( [ {
$group: { _id; "$author", x: { $sum: $likes } } } ] )

A. Sum of likes on all the posts by all the authors
B. Number of posts by an author
C. Average of likes on all the posts of an author, grouped by author
D. Sum of likes on all the posts by an author, grouped by author

正解：D

質問 # 38
MongoDB is

A. Object-oriented DBMS
B. Relational DBMS
C. Document-oriented DBMS
D. None of the above

正解：C

質問 # 39
What is the defau size of a GridFS chunk?

A. 255 K
B. 16 MB
C. 1 MB
D. 2 MB

正解：A

質問 # 40
Below is a sample document of "orders" collection

A. $project

正解：A

質問 # 41
Consider a collection posts which has fields: Jd, post_text, post_author, post_timestamp, post_tags etc.
Which of the following query retrieves ONLY the key named post_text from the first document retrieved?

A. db.posts.finOne({},{_id:0, post_text:1})
B. db.posts.finOne({},{post_text:1})
C. db.posts.find({},{_id:Of post_text:1})
D. db.posts.findOne({post_text: 1})

正解：A

質問 # 42
Suposse tou have the following collection with only 2 documents:

If you run an aggregation query and use { $unwind: "$traits" } as the first stage, how many documents will be passed to the next stage of the aggregation pipeline?

A. 0
B. 1
C. 2
D. 3
E. 4

正解：E

質問 # 43
Which of the following command inside aggregate command is used in MongoDB aggregation to filter the documents to pass only the documents that match the specified condition(s) to the next pipeline stage.

A. $sum
B. $aggregate
C. $match
D. $group

正解：C

質問 # 44
Which of the following is correct about MongoDB?

A. MongoDB supports collection joins
B. MongoDB supports some of the SQL functions
C. MongoDB supports geospatial indexes
D. MongoDB uses JSON format to represent documents

正解：C

質問 # 45
The following aggregation option is used to specify the specific fields that needs to be passed to the next stage of the aggregation pipeline:

A. $aggregate
B. $group
C. $match
D. $project

正解：D

質問 # 46
What does the following $slice query return using the following command? db.posts.find( {}, { comments: {
$slice: [ -10, 5 ] } } )

A. Returns 10 comments, beginning with the last
B. Returns 5 comments, beginning with the first 10 items
C. Returns 10 comments, beginning with the first
D. Returns 5 comments, beginning with the last 10 items

正解：D

質問 # 47
Consider the following document from the products collection:

What does the following query using $elemMatch return? db.products.find( { product_code: "345678" }, { variations: { $elemMatch: { size: ^L^ } } } )

A. Returns the complete document but retrieves only the size field from the array
B. Returns the document but with only one element in the variations array (corresponding to size L)
C. Returns the complete document since MongoDB does not support partial array retrieval
D. Returns the complete document but retrieves only the size field from the array and also with only one element in the variations array (corresponding to size L)

正解：B

質問 # 48
Consider the following document:
> db.c.find()
{ "_id" : 12, b : [ 3, 5, 7, 2, 1, -4, 3, 12 ] }
Which of the following queries on the "c" collection will return only the first five elements of the array in the
"b"
field? E.g.,
Document you want returned by your query:
{ "_id" : 12, "b" : [ 3, 5, 7, 2, 1 ] >

A. db.c.find( { > , { b : [ 0 , 5 ] > )
B. db.c.find( { > , { b : [ 0, 1, 2, 3, 4, 5 ] > )
C. db.c.find( { > , { b : { $slice : [ 0 , 5 ] } } )
D. db.c.find( { > , { b : { $substr[ 0 , 5 ] > > )
E. db.c.find( { b : [ 0 , 5 ] > )

正解：C

質問 # 49
The MongoDB explain() method does not support which of the following verbosity mode:

A. customExecutionStats
B. executionStats
C. allPlansExecution
D. queryPlanner

正解：A

質問 # 50
Which option should be used to update all the documents with the specified condition in the MongoDB query?

A. updateAII instead of update
B. specify {updateAII: true} as the third parameter of update command
C. specify {multi : true} as the third parameter of update command
D. specify {all: true} as the third parameter of update command

正解：C

質問 # 51
The________operator can be used to identify an element in the array to be updated without explicitly specifying the position of the element.