MongoError: E11000 duplicate key error collection: users index: mobile_1 dup key: { mobile: null }

Question

I created a user schema where I have a mobile field. The mobile field should be unique but still allow null values and should only compare uniqueness with strings. Here's my debug info:

The 'mobile' key inside my user schema

mobile: {
  type: String,
  index: {
    unique: true,
    partialFilterExpression: { mobile: { $type: 'string' } }
  },
}

mongoose debug log

Mongoose: users.createIndex({ mobile: 1 }, { unique: true, partialFilterExpression: { mobile: { '$type': 'string' } }, background: true})

Error

MongoError: E11000 duplicate key error collection: users index: mobile_1 dup key: { mobile: null }
    at Function.create (~/project/node_modules/mongodb/lib/core/error.js:44:12)
    at toError (~/project/node_modules/mongodb/lib/utils.js:150:22)
    at ~/project/node_modules/mongodb/lib/operations/common_functions.js:265:39
    at handler (~/project/node_modules/mongodb/lib/core/sdam/topology.js:971:24)
    at ~/project/node_modules/mongodb/lib/core/sdam/server.js:496:5
    at ~/project/node_modules/mongodb/lib/core/connection/pool.js:420:18
    at processTicksAndRejections (internal/process/task_queues.js:75:11) {
  driver: true,
  name: 'MongoError',
  index: 0,
  code: 11000,
  keyPattern: { mobile: 1 },
  keyValue: { mobile: null },
  errmsg: 'E11000 duplicate key error collection: users index: mobile_1 dup key: { mobile: null }',
  [Symbol(mongoErrorContextSymbol)]: {}
}

I tried a lot of options and different answers from stackoverflow but nothing seems to work so I'd like ask the proper way of doing this.

EDIT

The issue was that the code I had was correct, but I had to delete and re-create the table for it to work. Another solution would be to just remove the indexes.

Answer 1

The issue was that the code I had was correct, but I had to delete and re-create the table for it to work. Another solution would be to just remove the indexes.

Answer 2

After hours of googling, I finally found the problem

The problem was I was saving to a collection that I had previously used for another application with different userSchema that had several unique parameters like: phoneNumber, username ,...

But in my current models, I had just email and password as userSchema and I was getting this mongoError code 11000 with keyPattern: { username: null }

I just changed my Database_Url in my .env file (where I store my super secret data that don't want to hardcode in the app):

mongodb://127.0.0.1:27017/myNewCollectionName

and restarted the node with running:

npm start

then when i tried to register a user, I didn't get that error and it solved completely.

I hope this save your day ;)

Answer 3

I think you need a sparse index. Right now the unique index means you can only have one user with a null mobile value

From MongoDB docs on Sparse Indexes

Sparse indexes only contain entries for documents that have the indexed field, even if the index field contains a null value. The index skips over any document that is missing the indexed field. The index is “sparse” because it does not include all documents of a collection. By contrast, non-sparse indexes contain all documents in a collection, storing null values for those documents that do not contain the indexed field.

Here is an example of it for your code

users.createIndex({ mobile: 1 }, { 
  unique: true,  
  sparse: true, 
  partialFilterExpression: { mobile: { '$type': 'string' } }, 
  background: true})

Answer 4

Just match the database key and value if any key does not match with your code delete the entire database then again push the data

Answer 5

as per your error, you have to delete a document with same key value pair, you just keep one

Answer 6

from myside the simple solution is just delete(drop) your database. probably this might resolve the issue,such issue may happens because of redefining of that collection's Schema.