如何使用 mongoose 从 mongodb 模式中删除索引？

Question

I'm trying to remove an index from my mongoDB collection in node.js application using mongoose. I tried using model.collection.dropIndex("username") but it gives me an error UnhandledPromiseRejectionWarning: MongoError: index not found with name [username] .

Here is my Schema

var mongoose = require("mongoose"),
  Schema = mongoose.Schema;

var userTable = new Schema({
  firstname: { type: String, required: true },
  lastname: { type: String, required: true },
  username: { type: String },
  salt: { type: String },
  passwordHash: { type: String },
  email: { type: String, unique: true, required: true },
  sessionToken: { type: String },
  dateCreated: { type: String, default: new Date().toString() },
  loginHistory: [String]
});

module.exports = mongoose.model("userTable", userTable);

When I perform the query in mongo shell from the terminal using command db.usertable.find({}) , I can see that the results still have username field. I also tried after removing the username field from schema file, but even that didn't help.

Thanks in advance.

Answer 1

This drops all the indexes of the collection except for the object id

db.collection.dropIndexs();

to delete a certain index

first type the command

 db.collecction.getIndexes();

You will see something like above the in the red square is the index name .

db.collection.dropIndex( { "indexname": 1 } )

Answer 2

Creating an index using a unique name:

      db.collection('users')
      .createIndex(
        { email: 1 },
        { unique: true,
          name: 'users.email.unique_index' }, // here we set index name 
      );

and then drop the index using it's name:

 db.collection('users').dropIndex('users.email.unique_index');