express - UnhandledPromiseRejectionWarning: MongoError: E11000 duplicate key error collection: db.footballers index: data_1 dup key: { data: null }

Question

I have never had this issue before. I was creating instances easily all the time. But with this project it throwing me error about index or something. I don't even know what that is. Thank you in advance.

Here is my schema

const mongoose = require("mongoose");

const footballersSchema = new mongoose.Schema({
    name: {
        type: String,
        required: true,
        unique: true
    }
})

module.exports = mongoose.model('footballers', footballersSchema);

and is just simple controller which triggers creating a new instance

exports.checkUserForReg = async function(req, res, next){
            await footballersModel.create(req.body);
            res.(201).json({status: "Ok"})
}

but it gives me error UnhandledPromiseRejectionWarning: MongoError: E11000 duplicate key error collection: db.footballers index: data_1 dup key: { data: null }

Yes, every instance should have unique name field, but even when I try different it give me this error. I see error says index: data_1 dup key: { data: null }, but I don't have index key in my Schema at all! What is that ? Thank you!

Answer 1

等待大神解答