Removing duplicate records using MapReduce

Question

I\'m using MongoDB and need to remove duplicate records. I have a listing collection that looks like so: (simplified)

[
  { \"MlsId\": \"12345\"\" },
  { \"M         


        

Answer 1

this is how I following the @harri answer to remove duplicates:

//contains duplicated documents id and numeber of duplicates 
db.createCollection("myDupesCollection")
res = db.sampledDB.mapReduce(m, r, { out : "myDupesCollection" });

// iterate through duplicated docs and remove duplicates (keep one) 
db.myDupesCollection.find({value: {$gt: 1}}).forEach(function(myDoc){
    u_id = myDoc._id.MlsId;
    counts =myDoc.value;
    db.sampledDB.remove({MlsId: u_id},counts-1); //if there are 3 docs, remove 3-1=2 of them
});