dany dany - 1 year ago 190
Node.js Question

MongoError,err:E11000 duplicate key error

I have a MongoDb schema like this

var User = new Schema({
"UserName": { type: String, required: true },
"Email": { type: String, required: true, unique: true },
"UserType": { type: String },
"Password": { type: String }

I am trying to create a new user
This is done in NodeJs using mongoose ODM
And this is the code for creating:

controller.createUser = function (req, res) {

var user = new models.User({
"UserName": req.body.UserName.toLowerCase(),
"Email": req.body.Email.toLowerCase(),
"UserType": req.body.UserType.toLowerCase()
models.User.findOne({ 'Email': user.Email }, function (err, olduser) {
if (!err) {
if (olduser) {
res.send({ 'statusCode': 409, 'statusText': 'Email Already Exists' });
else if (!olduser) {
user.save(function (err, done) {
if (!err) {
res.send({ 'statusCode': 201, 'statusText': 'CREATED' });
else {
res.send({ 'Status code': 500, 'statusText': 'Internal Server Error' });
else {
res.send({ 'statusCode': 500, 'statusText': 'ERROR' });

The for creating new user,I am giving attributes and values as follows:

"UserName": "ann",
"Email": "ann@ann.com",
"UserType": "normaluser",

And I am getting error like this:

{"Status code":500,"statusText":"Internal Server Error","Error":{"name":"MongoError","err":"E11000 duplicate key error index: medinfo.users.$UserName_1 dup key: { : \"ann\" }","code":11000,"n":0,"connectionId":54,"ok":1}}

I understand that this error is because UserName is duplicated ,but I haven't set UserName with unique constraint.Whenever I add a new row,I need only email to be unique,UserName can be repeated.How to achieve this??

Answer Source

@ManseUK Is probably right, that looks like UserName is a 'key' - in this case an index. The _id attribute is the "primary" index that is created by default, but mongodb allows you to have multiple of these.

Start a mongo console and run medinfo.users.getIndexes()? Something must have added an index on 'UserName'.

required: true wouldn't do that, but you might have played with other settings previously and the index hasn't been removed?

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