I am iterating over a collection, and for each document, I am removing an element with the lowest score from the scores array.
MongoClient.connect('mongodb://localhost:27017/school', function(err, db) {
if(err) throw err;
//var query = { 'assignment' : 'hw1' };
//var operator = { '$set' : { 'date_returned' : new Date() } };
var students = db.collection('students');
var updateDoc = function(document){
"use strict"
console.log('update called');
db.collection('students').save(document,function(error,updatedDocument){
if(error){
console.log(error);
throw error;
}
console.dir('successfully updated document: '+updatedDocument);
});
}
var cursor = students.find({});
cursor.each(function(error,doc){
"use strict"
if(err) throw err;
if(doc==null){
return;
}
doc.scores.sort(function(a,b){
return a.score-b.score;
});
doc.scores.splice(0,1);
updateDoc(doc);
});
});
Some of the documents are updated, but I get an error at some point like this.
{ [MongoError: E11000 duplicate key error index: school.students.$_id_ dup key:
{ : 0 }]
name: 'MongoError',
err: 'E11000 duplicate key error index: school.students.$_id_ dup key: { : 0
}'.......
I can understand that I am doing something wrong relating to asynchronous operation on the db, but I am not able to figure out the exact cause.
Help will be appreciated. Thanks
EDIT: document sample
{ _id: 198,
name: 'Timothy Harrod',
scores:
[
{ type: 'exam', score: 11.9075674046519 },
{ type: 'quiz', score: 20.51879961777022 },
{ type: 'homework', score: 55.85952928204192 },
{ type: 'homework', score: 64.85650354990375 }
]
}
