C100DBA MongoDB Certified DBA Associate Exam (Based on MongoDB 4.4) Questions and Answers

db.collection.update({b:456>, {$inc: {a:l> })

db.collection.find( {a : 232} )

db.collection.insert( { a:341})

0

1

2

3

5

Concurrency Control

Atomicity

Performance Management

Transaction Management

upsert command instead of update command

{update: true, insert: true} as the third parameter of update command

This has to be handled in application code (Node.js, PHP, JAVA, C#, etc.) and cannot be handled in mongo shell query

Specify {upsert : true } as the third parameter of update command

Fixed Size

Only "Fixed Size" and "High-throughput operations that insert and retrieve documents based on insertion order"

High-throughput operations that insert and retrieve documents based on insertion order

If the allocated space for a capped collection exceeds, it stops inserting new documents

{ "-id" : Objectld("580a42b5dfblb5al7427d302"), "nombre" : "ruben", "apellido" : "gomez", "aficion" : v u "flipar" }

{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "Luis", "apellido" : "gomez", "aficion" : u "flipar" }

{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "Pablo" , "aficion" : u "flipar"}

{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "gomez" >

Code block

Name/value pair

Key

None of the above

$arrayLimit

$push along with $each, $sort and $slice

$removeFromSet

None of the above

db.posts.find( { post_timestamp: { $fieldtype: null } } )

db.posts.find( { post_timestamp: { $type: null } } )

db.posts.find( { post_timestamp : { $type; 10 > > )

db.posts.find( { post_timestamp: { $fieldtype: 10 } } )

upsert command instead of update command

This has to be handled in application code (Node.js, PHP, JAVA, C#, etc.) and cannot be handled in mongo shell query

{update: true, insert: true} as the third parameter of update command

Specify {upsert : true } as the third parameter of update command

The write operations on the collection are low

The write operations on the collection are very high

The working set in the collection is expected to grow very large in size

The collection is a read intensive collection with less working set

db.collection.createlndex({relndex:l})

db.collection.reIndex({author:l})

db.collection.relndexQ

db.collection.createIndex({author:l}).reIndex()

missing operations will need to be manually re-performed

the secondary with the most current oplog will be elected primary

reads will be stale until the primary comes back up

the primary may roll back the operations once it recovers

the most current secondary will roll back the operations following the election

BSON

JSON

SOAP

XML

findQ returns all the documents in a collection while findOne() retrieves only the first one.

find.limit(l) is not the same query as findOne()

findOneQ returns the actual first document retrieved from a collection

findQ and findOneQ returns cursors to the collection documents

Skip and limit nullify each other. Hence returning the first five documents.

Skips the first five documents and returns the next five

Limits the first five documents and then return them in reverse order

Skips the first five documents and returns the sixth document five times