Question $1$ Consider a collection posts which has fields: $\_$id$,$ post$\_$text, post$\_$author, post$\_$timestamp, post$\_$tags etc. Which query retrieves ONLY the key named post$\_$text from the first document retrieved? db$.$posts.find$(\{\},\{\_$id:$0,$ post$\_$text:$1\})$ db$.$posts.findOne$(\{$post$\_$text:$1\})$ db$.$posts.findOne$(\{\},\{$post$\_$text:$1\})$ db$.$posts.findOne$(\{\},\{\_$id:$0,$ post$\_$text:$1\})5$ points Question $2$ Which of the following is an incorrect statement about find and findOne operations in MongoDB? find$()$ returns all the documents in a collection while findOne$()$ retrieves only the first one. find$()$ and findOne$()$ return cursors to the collection documents findOne$()$ returns the actual first document retrieved from a collection $5$ points Question $3$ What does the following MongoDB command return? db$.$posts.find$(\{$ likes : $\{$ $gt : $100,$ $lt : $200\}\})$ Posts with likes greater than $100$ but less than $200$ Posts with likes greater than or equal to $100$ but less than or equal to $200$ Posts with likes less than $200$ Will return syntax error $6$ points Question $4$ Which command finds all documents in the posts collection with a date$\_$inserted field as null? db$.$posts.find$(\{$date$\_$inserted: null$\})$ db$.$posts.find$($date$\_$inserted: null $)$ db$.$posts.find$(\{$date$\_$inserted: isnull$\})5$ points Question $5$ What does the following MongoDB command return? db$.$posts.find$(\{$ likes : $\{$ $gt : $100\},$ likes : $\{$ $lt : $200\}\})$ Posts with likes greater than $100$ but less than $200$ Posts with likes greater than or equal to $100$ but less than or equal to $200$ Posts with likes less than $200$ Will return syntax error $6$ points Question $6$ Which command will find all the posts that have a topic$\_$category as logic. db$.$posts.find$(\{$ topic$\_$category : $"$ logic $"\})$ db$.$posts.find$(\{$ topic$\_$category : $["$logic $"]\})$ db$.$posts.find$(\{$ $array : $\{$ topic$\_$category: $"$ logic $"\}\})$ db$.$posts.findInArray$(\{$ topic$\_$category : $"$ logic $"\})5$ points Question $7$ Consider that our posts collection contains an array field called tags that contains tags that the user enters. $\{\_$id: $1,$ tags: $["$tutorial$",$ "fun", "learning"$],$ post$\_$text: "This is my first post", topic$\_$category: "lecture"$\}$ What does the following command return? db$.$posts.find$(\{$ "tags$\mathrm{.}0"$: "tutorial" $\})$ All the posts whose tags array contains tutorial All the posts which contains only one tag element in the tag array All the posts having the first element of the tags array as tutorial All the posts which contains $0$ or more tags named tutorial $5$ points Question $8$ Consider that the posts collection contains an array called ratings which contains ratings given to the post by various users in the following format: $\{\_$id: $1,$ post$\_$text: "This is my first post", ratings: $[5,4,2,5],//$other elements of document $\}$ Which query will return all the documents where the array ratings contains at least one element between $3$ and $6?$ db$.$inventory.find$(\{$ ratings: $\{$ $elemMatch: $\{$ $gt: $3,$ $lt: $6\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ ratings: $\{$ $gt: $5,$ $lt: $9\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ ratings.$: $\{$ $gt: $5,$ $lt: $9\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ $elemMatch: $\{$ $gte: $3,$ $lte: $6\}\}\})5$ points Question $9$ Consider that the posts collection contains an array called ratings which contains ratings given to the post by various users in the following format: $\{$ id: $1,$ post$\_$text: "This is my first post", ratings: $[5,4,2,5],//$other elements of document $\}$ Which query will return all the documents where the ratings array contains elements that in some combination satisfy the query conditions? db$.$inventory.find$(\{$ ratings: $\{$ $elemMatch: $\{$ $gt: $3,$ $lt: $6\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ ratings: $\{$ $gt: $5,$ $lt: $9\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ ratings.$: $\{$ $gt: $5,$ $lt: $9\}\}\})$ db$.$inventory.find$(\{$ ratings: $\{$ $elemMatch: $\{$ $gte: $3,$ $lte: $6\}\}\})5$ points Question $10$ Consider the following posts document: $\{$ id: $1,$ post$\_$text: "This is my first post", author: "Tom", tags: $["$tutorial$",$"quiz","facebook","learning","fun"$]\}$ Which of the following queries will return the documents but with only the first two tags in the tags array? db$.$posts.find$(\{$author:"Tom"$\},\{$tags:$\{$$slice:$2\}\})$ db$.$posts.find$(\{$author:"Tom"$\}).$limit$(\{$tags:$2\})$ db$.$posts.find$(\{$author:"Tom"$\}).$limit$($$slice:$\{$tags:$2\})$ Both a and c are valid. $slice works both with projection and limit$.5$ points Question $11$ What is the equivalent command in MongoDB for the following SQL query? SELECT $*$ FROM posts WHERE author like $"\%$john$\%"$ db$.$posts.find$(\{$ author: $/$john$/\})$ db$.$posts.find$(\{$ author: $\{$$like: $/$john$/\}\})$ db$.$posts.find$(\{$ $like: $\{$author: $/$john$/\}\})$ db$.$posts.find$(\{$ author: $/^$john$^/\})5$ points