Sample_mongodb_certification_

Section 1: Philosophy & Features:
1. Which of the following does MongoDB use to provide High Availability and fault tolerance?

a. Write Concern # Write concern describes the level of acknowledgement requested from MongoDB for write operations to a standalone mongod or to replica sets or to sharded clusters. In sharded clusters, mongos instances will pass the write concern on to the shards.

* b. Replication # provê o HA

c. Sharding # é a distribuição do dado

d. Indexing # index

2. Which of the following does MongoDB use to provide High Scalability?

a. Write Concern

b. Replication

c. Sharding # escalavel.

d. Indexing

Section 2: CRUD Operations:
1. Which of the following is a valid insert statement in mongodb? Select all valid.

a. db.test.insert({x:2,y:”apple”}) # correto

b. db.test.push({x:2,y:”apple”}) # push?

c. db.test.insert({“x”:2, “y”:”apple”}) # correto

d. db.test.insert({x:2},{y:”apple”}) # errado

Section 3: Aggregation Framework:
1. Which of the following is true about aggregation framework?

a. A single aggregation framework operator can be used more than once in a query
	Um único operador de estrutura de agregação pode ser usado mais de uma vez em uma consulta
	
b. Each aggregation operator need to return atleast one of more documents as a result
	Cada operador de agregação precisa retornar pelo menos um ou mais documentos como resultado

c. Pipeline expressions are stateless except accumulator expressions used with $group operator
	Expressões de pipeline são sem estado, exceto as expressões de acumulador usadas com o operador $ group
	
d.  the aggregate command operates on a multiple collection #falso

Section 4: Indexing:
Below is a sample document in a given collection test.

{ a : 5, b : 3, c: 2, d : 1 }

1. Given a compound index { a: 1, b:1, c:1, d:1}, Which of the below query will not use in-memory sorting? Select all valid.

a. db.test.find( { a: 5, b: 3 } ).sort( { a: 1, b: 1, c: 1 } )

b. db.test.find( { a: 5, b: 3 } ).sort( { a: 1} )

c. db.test.find( { a: 5, b: 3 } ).sort( {c: 1 } ) # correto
 
d. db.test.find( { a: 5, b: 3 } ).sort( { c: 1, d : 1 } ) # correto

Section 5: Replication:
1. In a replicated cluster, which of the following node would only be used during an election?

a. primary

b. secondary

c. arbiter # -

d. hidden

2. What  is the first task that a secondary would perform on being prompted by another secondary for an election?

a. Start the election process for primary

b. Connect to primary to confirm its availability # -

c. Vote for the first secondary so that it would become the next primary

d. Vote for itself and then call for election

Section 6: Sharding:
1. In which of the following scenarios is sharding not the correct option. Select all that apply.

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

b. The write operations on the collection are low # -

c. The collection is a read intensive collection with less working set # -

d. The write operations on the collection are very high

Section 7: Server & Application Administration:
1. Which of the following collections stores authentication credentials in MongoDB?

a. system.users

b. local.users

c. test.users

d. users.users

Section 8: Backup & Restore:
1. In a sharded cluster, from which node does one stop the balancer process before initiating backup?

a. Any node

b. mongos node

c. config server node

d. replicaset primary node

https://blog.cloudthat.com/sample-questions-for-mongodb-certified-dba-c100dba-exam/
https://blog.cloudthat.com/mongodb-certified-dba-associate-exam/