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

Comment: *

Name: *

Email: *

Verification: *

To add a new user and enable authentication in MongoDB, which of the following steps need be executed?

• A.update users collection and restart mongodb
• B.update users collection and run db.enableAuthenticationQ
• C.update users collection and restart mongodb with -auth option
• D.All of the above

Comment: *

Name: *

Email: *

Verification: *

Consider that you have a collection called population which has fields state and city. Which of the following query will calculate the population grouped by state and city?

• A.db.population.aggregate( [{ $group: { _id: { state: "$state", city; "$city" },pop: { $sum: 1 > > >] )
• B.db.population.aggregate( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $pop: 1 } } }] )
• C.db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB
• D.db.population.aggregate( [{ $group: { _id: { state: Estate", city: n$city" },pop: { $sum: "$pop" } } }] )

Comment: *

Name: *

Email: *

Verification: *

Dada una coleccion, cuales devuelve con la siguiente query
db.coleccion.find({nombre:"ruben",apellido:"gomez"},{nombre:l,apellido:l,aficion:l});

• A.{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "gomez" >
• B.{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "Luis", "apellido" : "gomez", "aficion" : u
  "flipar" }
• C.{ "-id" : Objectld("580a42b5dfblb5al7427d302"), "nombre" : "ruben", "apellido" : "gomez", "aficion" :
  v u "flipar" }
• D.{ "_id" : Objectld("580a42acdfblb5al7427d301"), "nombre" : "ruben", "apellido" : "Pablo" , "aficion" : u
  "flipar"}

Comment: *

Name: *

Email: *

Verification: *

Which are the ONLY ways to project portions of an array?

• A.All of the above
• B.$
• C.$slice
• D.$ elemMatch

Comment: *

Name: *

Email: *

Verification: *