C100DBA Questions and Answers

False

True

db.population.aggregate( [{ $group: { _id: { state: "$state", city; "$city" },pop: { $sum: 1 > > >] )

db.population.aggregate( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $pop: 1 } } }] )

db.population.aggregate( [{ $group: { _id: { state: Estate", city: n$city" },pop: { $sum: "$pop" } } }] )

db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB

7

03

04

06

All of the above

Inserting data

Map-reduce

Issuing a query

A document will be inserted with the same _id as the last document inserted

A document that matches the collection's existing schema, but with null fields

A document with an _id assigned to be an Objectld

An empty document

No document will be inserted; an error will be raised

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 } } )

Batch data insertion

None of the above

Multiple command import

Multiple command insertion

<replicasetid>.oplog.rs

oplog.rs

..oplog.rs

local.oplog.rs

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

db. posts.createIndex({^comments.author" :1});

db.posts.createIndex({^commerits.author";-!});

All of the above

Compound Indexes

Multikey Indexes

Geospatial Indexes

$set

$update

$project

$modify

255 K

1 MB

16 MB

2 MB

Sharding

Properly defined user roles

Replication

Put indexes on all of your documents

The proper storage engine