Olete.in – MCQs, Mock Tests & Government Job Prep | MongoDB MongoDB Mcq Question Set 3

Which of the following function is valid for creation of new data inside MongoDB Shell?

1. function insertData(dbName, colName, num) { var col = db.getSiblingDB(dbName).getCollection(colName); for (i = 0; i < num; i++) { col.insertData({x:i}); } print(col.count()); }
2. function insertData(dbName, colName, num) { var col = db.getSiblingDB(dbName).getCollection(colName); for (i = 0; i < num; i++) { col.insert({x:i}); } print(col.count()); }
3. insertData(dbName, colName, num) { var col = db.getSiblingDB(dbName).getCollection(colName); for (i = 0; i < num; i++) { col.insert({x:i}); } print(col.count()); }
4. None of the mentioned

✅ Correct Answer: 2

Point out the wrong statement.

1. Database is a physical container for collections
2. A single MongoDB server typically has single databases
3. Collection is the equivalent of an RDBMS table
4. None of the mentioned

✅ Correct Answer: 2

_id is a ________ bytes hexadecimal number which assures the uniqueness of every document.

1. 13
2. 16
3. 12
4. 10

✅ Correct Answer: 3

Which of the following statement will insert 400 documents in to the testData collection?

1. insertData("test", "testData", 200)
2. insertData("test", "testData", 400)
3. insertData("test", "testData", 600)
4. All of the Mentioned

✅ Correct Answer: 2

The mongo shell loads and parses the ___________ file on startup.

1. mongo.js
2. mongoc.js
3. mongorc.js
4. All of the Mentioned

✅ Correct Answer: 3

To iterate the cursor and return more documents, type _________ in the mongo shell.

1. cursor
2. it
3. next
4. None of the mentioned

✅ Correct Answer: 2

Which of the following key is used to denote uniqueness in the collection?

1. _id
2. id
3. id_
4. None of the mentioned

✅ Correct Answer: 1

A query may include a ___________ that specifies the fields from the matching documents to return.

1. selection
2. projection
3. union
4. None of the mentioned

✅ Correct Answer: 2

Point out the correct statement.

1. Secondary indexes allow applications to store a view of a portion of the collection in an efficient data structure
2. MongoDB has full support for secondary indexes
3. Most indexes store an ordered representation of all values of a field or a group of fields
4. All of the Mentioned

✅ Correct Answer: 2

MongoDB stores all documents in _______

1. tables
2. collections
3. rows
4. All of the Mentioned

✅ Correct Answer: 2

In MongoDB _________ operations modify the data of a single collection.

1. CRUD
2. GRID
3. READ
4. All of the Mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. Indexes cannot enforce uniqueness in collection
2. CRUD stands for create, read, update, and delete
3. CRUD application is the most simplest application
4. All of the Mentioned

✅ Correct Answer: 1

Which of the following operation adds a new document to the users collection?

1. add
2. insert
3. truncate
4. drop

✅ Correct Answer: 2

Which of the following preference determines how the client direct read operations to the set?

1. read
2. write
3. update
4. delete

✅ Correct Answer: 1

Applications can also control the behavior of write operations using _______ concern.

1. read
2. write
3. truncate
4. All of the Mentioned

✅ Correct Answer: 2

MongoDB process collection of documents using _________ operations.

1. Hbase
2. Hive
3. Map-reduce
4. None of the mentioned

✅ Correct Answer: 3

Which of the following pipeline is used for aggregation in MongoDB?

1. data processing
2. information processing
3. knowledge processing
4. None of the mentioned

✅ Correct Answer: 1

The order of documents returned by a query is not defined unless you specify a ______

1. sortfind()
2. sortelse()
3. sort()
4. none of the mentioned

✅ Correct Answer: 3

Point out the correct statement.

1. Queries specify criteria, or conditions, that identify the documents that MongoDB returns to the clients
2. Write operations, or queries, retrieve data stored in the database
3. The selection limits the amount of data that MongoDB returns to the client over the network
4. All of the Mentioned

✅ Correct Answer: 1

In aggregation pipeline, the _______ pipeline stage provides access to MongoDB queries.

1. $catch
2. $match
3. $batch
4. All of the Mentioned

✅ Correct Answer: 2

Which of the following method returns one document?

1. findOne()
2. findOne1()
3. selectOne()
4. All of the Mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. sort() modifier sorts the results by age in ascending order
2. Queries in MongoDB return all fields in all matching documents by default
3. To scale the amount of data that MongoDB sends to applications, include a projection in the queries.
4. none of the mentioned

✅ Correct Answer: 3

Which of the following is the second argument to projection?

1. findOne()
2. findOne1()
3. selectOne()
4. find()

✅ Correct Answer: 4

Which of the following query selects documents in the records collection that match the condition { “user_id”: { $lt: 42 } }?

1. db.records.findOne( { “user_id”: { $lt: 42 } }, { “history”: 0 } )
2. db.records.find( { “user_id”: { $lt: 42 } }, { “history”: 0 } )
3. db.records.findOne( { “user_id”: { $lt: 42 } }, { “history”: 1 } )
4. db.records.select( { “user_id”: { $lt: 42 } }, { “history”: 0 } )

✅ Correct Answer: 2

Which of the following functionality is used for aggregation framework?

1. $match
2. $project
3. $projectmatch
4. All of the mentioned

✅ Correct Answer: 2

To suppress the _id field from the result set, specify _________ in the projection document.

1. _id: 1
2. _id: 0
3. _id: it
4. None of the mentioned

✅ Correct Answer: 2

Which of the following is not a projection operator?

1. $slice
2. $elemMatch
3. $
4. None of the mentioned

✅ Correct Answer: 4

Which of the following flag can be set by mongo shell?

1. Timeout
2. noTimeout
3. Time
4. None of the mentioned

✅ Correct Answer: 2

Point out the correct statement.

1. Intervening read operations on a document may result in a cursor that returns a document more than once if that document has changed
2. The MongoDB server returns the query results in batches
3. Subsequent batch size is 50 megabytes
4. None of the mentioned

✅ Correct Answer: 2

Which of the following will display complete list of available cursor flags?

1. cursor.Option()
2. cursor.addOption()
3. cursor.addOptions()
4. All of the Mentioned

✅ Correct Answer: 2

To describe the message structure, a ________ like struct is used.

1. Pascal
2. C++
3. C
4. Java

✅ Correct Answer: 3

Point out the wrong statement.

1. The MongoDB Wire Protocol is a simple socket-based, request-response style protocol
2. For queries that include a sort operation without an index, the server must load all the documents in memory to perform the sort before returning any results
3. Clients communicate with the database server through a regular TCP/IP socket
4. All of the mentioned

✅ Correct Answer: 4

____ specifies the number of documents to return in each batch of the response from the MongoDB instance.

1. cursor.batchSize(size)
2. cursor.Size(size)
3. cursor.batch(size)
4. All of the Mentioned

✅ Correct Answer: 1

The __________ method returns a document that includes a metrics field.

1. db.serverStats()
2. db.serverStatus()
3. db.status()
4. All of the Mentioned

✅ Correct Answer: 2

________ is a client or database-generated identifier that uniquely identifies this message.

1. messageLength
2. responseTo
3. requestID
4. All of the Mentioned

✅ Correct Answer: 3

Which of the following operator is not very selective?

1. $nine
2. $nin
3. $ain
4. None of the mentioned

✅ Correct Answer: 2

An index cannot cover a query on a _______ collection when run against a mongos if the index does not contain the shard key.

1. vertical
2. sharded
3. horizontal
4. None of the mentioned

✅ Correct Answer: 2

______ concern describes the guarantee that MongoDB provides when reporting on the success of a write operation.

1. Write
2. Read
3. Update
4. None of the mentioned

✅ Correct Answer: 1

Point out the correct statement.

1. Read operations on sharded clusters are most efficient when directed to a specific shard
2. Sharded clusters allow you to partition a data set among a cluster of mongod instances in a way that is nearly transparent to the application
3. For a sharded cluster, applications issue operations to one of the mongos instances associated with the cluster
4. All of the Mentioned

✅ Correct Answer: 4

When inserts, updates and deletes have a _________ write concern, write operations return quickly.

1. strong
2. weak
3. average
4. very strong

✅ Correct Answer: 2

The mongo shell and the MongoDB drivers use __________ as the default write concern.

1. Nacknowledged
2. Acknowledgement
3. Acknowledged
4. All of the mentioned

✅ Correct Answer: 3

Point out the wrong statement.

1. When a query does not include a shard key, the mongos can use cluster metadata from the config database to route the queries to shards
2. On larger clusters, scatter gather queries are unfeasible for routine operations
3. Replica sets use read preferences to determine where and how to route read operations to members of the replica set
4. None of the mentioned

✅ Correct Answer: 1

_______ is used to control mongod commits in the journal.

1. commitIntervMs
2. commitInterval
3. commitIntervalMs
4. All of the Mentioned

✅ Correct Answer: 3

Clients can set a __________ value as part of a replica acknowledged write concern.

1. timeout
2. wtimeout
3. waittimeout
4. None of the mentioned

✅ Correct Answer: 2

MongoDB does not ___________ modifications made before the wtimeout interval expired.

1. commit
2. rollback
3. save
4. All of the Mentioned

✅ Correct Answer: 2

With an __________ write concern, MongoDB does not acknowledge the receipt of write operations.

1. Nacknowledged
2. Acknowledgement
3. Acknowledged
4. Unacknowledged

✅ Correct Answer: 4

With a receipt acknowledged write concern, the _________confirms that it received the write operation and applied the change to the in-memory view of data.

1. mongod
2. mongos
3. mongo
4. mongoc

✅ Correct Answer: 1

Indexes are typically available in ______ or located sequentially on disk.

1. RAM
2. ROM
3. CMOS
4. None of the mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. Query selectivity refers to how well the query predicate excludes or filters out documents in a collection
2. Query selectivity can determine whether or not queries can use indexes effectively or even use indexes at all
3. More selective queries match a larger percentage of documents
4. All of the Mentioned

✅ Correct Answer: 3

______ is used to determine whether a query is a covered query.

1. explainstats()
2. explain()
3. explainall()
4. All of the Mentioned

✅ Correct Answer: 2