Hi,
I have two model, challenge(embeds_many :tasks) and task(embedded_in :challenge), finally database structue is like this
{ "_id" : ObjectId("4db8b0524f0b495c3a7dbba4"), "title" : "Testing1", "created" : ISODate("2011-12-12T00:00:00Z"), "tasks" : [ { "name" : "task no 1", "score" : "5" }, { "name" : "task no2", "score" : "6" } ] }
{ "_id" : ObjectId("4db8b0524f0b495c3a7dbba5"), "title" : "Testing2", "created" : ISODate("2011-12-12T00:00:00Z"), "tasks" : [ { "name" : "task no 1", "score" : "7" }, { "name" : "task no2", "score" : "8" } ] }
Here i have to select top 5 challenges having highest task score. I am using mongodb as database and i come to know there is concept of "Map/reduce grouping" but not able to figure it out.
i was writting this code in my controller but it become more complicated.
def whowins @challenge = Challenge.where(:_id => "4ef1a6a454b53001a4000067").first $wins ={"first"=>{"id"=>"1", "score"=>"1"},"second"=>{"id"=>"2", "score"=>"2"},"third"=>{"id"=>"3", "score"=>"3"},"fourth"=>{"id"=>"4", "score"=>"4"},"fifth"=>{"id"=>"5", "score"=>"5"}} temp ={"id"=>"10","score"=>"20"} aTotalScore = 0
if @challenge.instance_of?Challenge
@challenge.tasks.each_with_index do |orgTasks,index| aTotalScore += orgTasks.score.to_i end $wins["first"]["id"]= @challenge.user_id $wins["first"]["score"]= aTotalScore aTotalScore = 0
@challenge.child_challenges.each do |aChildChallenge| aChildChallenge.tasks.each_with_index do |eachTasks,index| aTotalScore += eachTasks.score.to_i end #raise aTotalScore.inspect if aTotalScore > $wins["first"]["score"] #raise "first less" whoWinning aTotalScore, $wins["first"]["score"], aChildChallenge.user_id, 1 aTotalScore = 0 next if aTotalScore = 0 elsif aTotalScore > $wins["second"]["score"] #raise "decond less" whoWinning aTotalScore, $wins["second"]["score"], aChildChallenge.user_id, 2 aTotalScore = 0 next if aTotalScore = 0 elsif aTotalScore > $wins["third"]["score"] #raise "third less" whoWinning aTotalScore, $wins["third"]["score"], aChildChallenge.user_id, 3 aTotalScore = 0 next if aTotalScore = 0 elsif aTotalScore > $wins["fourth"]["score"] #raise "fourht less" whoWinning aTotalScore, $wins["fourth"]["score"], aChildChallenge.user_id, 4 aTotalScore = 0 next if aTotalScore = 0 else #raise "fifth less" whoWinning aTotalScore, $wins["fifth"]["score"], aChildChallenge.user_id, 5 aTotalScore = 0 next if aTotalScore = 0 end end
else raise "childchallenge" end end
private
def whoWinning(tempScore, winnerScore, winnerId, aPossition ) aTScore = 0 aTId = 0 if aPossition == 5 $wins["fifth"]["score"],$wins["fifth"]["id"] = tempScore,winnerId raise $wins.inspect return else if aPossition == 1 aTScore,$wins["first"]["score"] = $wins["first"]["score"],tempScore aTId = $wins["second"]["id"] $wins["second"]["score"],$wins["first"]["id"] = aTScore,winnerId if $wins["third"]["score"].to_i > $wins["second"]["score"] whoWinning $wins["third"]["score"], $wins["second"]["score"], aTId, 2 else return end end
if aPossition == 2 aTScore,$wins["second"]["score"] = $wins["second"]["score"],tempScore aTId = $wins["third"]["id"] $wins["third"]["score"],$wins["second"]["id"] = aTScore,winnerId if $wins["fourth"]["score"] > $wins["third"]["score"] whoWinning $wins["fourth"]["score"], $wins["third"]["score"], aTId, 3 else return end end
if aPossition == 3 aTScore,$wins["third"]["score"] = $wins["third"]["score"],tempScore aTId = $wins["fourth"]["id"] $wins["fourth"]["score"],$wins["third"]["id"] = aTScore,winnerId if $wins["fifth"]["score"] > $wins["fourth"]["score"] whoWinning $wins["fifth"]["score"], $wins["fourth"]["score"], aTId, 4 else return end end
if aPossition == 4 aTScore,$wins["fourth"]["score"] = $wins["fourth"]["score"],tempScore aTId = $wins["fifth"]["id"] $wins["fifth"]["score"],$wins["fourth"]["id"] = aTScore,winnerId #whoWinning $wins["fifth"]["score"], $wins["fourth"]["score"], aTId, 5 end end end
I m new to mongodb, any help or suggetion will be highly apreciated. Tks in advance