The solution to HOMEWORK 4.1 M101JS: MongoDB FOR NODE.JS DEVELOPERS
Suppose you have a collection with the following indexes:
> db.products.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "store.products",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"sku" : 1
},
"unique" : true,
"ns" : "store.products",
"name" : "sku_1"
},
{
"v" : 1,
"key" : {
"price" : -1
},
"ns" : "store.products",
"name" : "price_-1"
},
{
"v" : 1,
"key" : {
"description" : 1
},
"ns" : "store.products",
"name" : "description_1"
},
{
"v" : 1,
"key" : {
"category" : 1,
"brand" : 1
},
"ns" : "store.products",
"name" : "category_1_brand_1"
},
{
"v" : 1,
"key" : {
"reviews.author" : 1
},
"ns" : "store.products",
"name" : "reviews.author_1"
}
Which of the following queries can utilize at least one index to find all matching documents or to sort? Check all that apply.
Solutions:
db.products.find( { ‘brand’ : “GE” } ).sort( { price : 1 } )
db.products.find( { $and : [ { price : { $gt : 30 } },{ price : { $lt : 50 } } ] } ).sort( { brand : 1 } )
I have submitted those two answers and found it to be correct.
Let me know if you have any problems.
