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.