How to drop a database with Mongoose?

Question

I'm preparing a database creation script in Node.js and Mongoose. How can I check if the database already exists, and if so, drop (delete) it using Mongoose?

I could not find a way to drop it with Mongoose.

Answer 1

There is no method for dropping a collection from mongoose, the best you can do is remove the content of one :

Model.remove({}, function(err) { 
   console.log('collection removed') 
});

But there is a way to access the mongodb native javascript driver, which can be used for this

mongoose.connection.collections['collectionName'].drop( function(err) {
    console.log('collection dropped');
});

Warning

Make a backup before trying this in case anything goes wrong!

Answer 2

Mongoose will create a database if one does not already exist on connection, so once you make the connection, you can just query it to see if there is anything in it.

You can drop any database you are connected to:

var mongoose = require('mongoose');
/* Connect to the DB */
mongoose.connect('mongodb://localhost/mydatabase',function(){
    /* Drop the DB */
    mongoose.connection.db.dropDatabase();
});

Answer 3

If you modify @hellslam's solution like this then it will work

I use this technique to drop the Database after my integration tests

//CoffeeScript
mongoose = require "mongoose"
conn = mongoose.connect("mongodb://localhost/mydb")

conn.connection.db.dropDatabase()

//JavaScript
var conn, mongoose;
mongoose = require("mongoose");
conn = mongoose.connect("mongodb://localhost/mydb");

conn.connection.db.dropDatabase();

HTH at least it did for me, so I decided to share =)

Answer 4

Tried @hellslam's and @silverfighter's answers. I found a race condition holding my tests back. In my case I'm running mocha tests and in the before function of the test I want to erase the entire DB. Here's what works for me.

var con = mongoose.connect('mongodb://localhost/mydatabase');
mongoose.connection.on('open', function(){
    con.connection.db.dropDatabase(function(err, result){
        done();
    });
});

You can read more https://github.com/Automattic/mongoose/issues/1469

Answer 5

An updated answer, for 4.6.0+, if you have a preference for promises (see docs):

mongoose.connect('mongodb://localhost/mydb', { useMongoClient: true })
.then((connection) => {
   connection.db.dropDatabase();
   // alternatively:
   // mongoose.connection.db.dropDatabase();
});

I tested this code in my own code, using mongoose 4.13.6. Also, note the use of the useMongoClient option (see docs). Docs indicate:

Mongoose's default connection logic is deprecated as of 4.11.0. Please opt in to the new connection logic using the useMongoClient option, but make sure you test your connections first if you're upgrading an existing codebase!

Answer 6

The difficulty I've had with the other solutions is they rely on restarting your application if you want to get the indexes working again.

For my needs (i.e. being able to run a unit test the nukes all collections, then recreates them along with their indexes), I ended up implementing this solution:

This relies on the underscore.js and async.js libraries to assemble the indexes in parellel, it could be unwound if you're against that library but I leave that as an exerciser for the developer.

mongoose.connection.db.executeDbCommand( {dropDatabase:1}, function(err, result) {
  var mongoPath = mongoose.connections[0].host + ':' + mongoose.connections[0].port + '/' + mongoose.connections[0].name
  //Kill the current connection, then re-establish it
  mongoose.connection.close()
  mongoose.connect('mongodb://' + mongoPath, function(err){
    var asyncFunctions = []

    //Loop through all the known schemas, and execute an ensureIndex to make sure we're clean
    _.each(mongoose.connections[0].base.modelSchemas, function(schema, key) {
      asyncFunctions.push(function(cb){
        mongoose.model(key, schema).ensureIndexes(function(){
          return cb()
        })
      })
    })

    async.parallel(asyncFunctions, function(err) {
      console.log('Done dumping all collections and recreating indexes')
    })
  })
})

Answer 7

This works for me as of Mongoose v4.7.0:

mongoose.connection.dropDatabase();

Answer 8

2020 update

make a new file call it drop.js i.e and put inside

require('dotenv').config()
const url = process.env.ATLAS_URI;
mongoose.connect(url, {
  useNewUrlParser: true,
  useCreateIndex: true,
  useUnifiedTopology: true,
  useFindAndModify: false
});

const connection = mongoose.connection;
connection.once('open', () => {
  console.log("MongoDB database connection established successfully");
})


mongoose.connection.dropDatabase().then(
  async() => {
   
    try {
      mongoose.connection.close()
     
    }
    catch (err) {
      console.log(err)
    }

 }
  
);

in your package.json

in your package.json 
 "scripts": {
    
    "drop": "node models/drop.js",
   
  }

run it on ur console and

Answer 9

To empty a particular collection in a database:

model.remove(function(err, p){
    if(err){ 
        throw err;
    } else{
        console.log('No Of Documents deleted:' + p);
    }
});

Note:

1. Choose a model referring to particular schema(schema of collection you wish to delete).
2. This operation will not delete collection name from database.
3. This deletes all the documents in a collection.

Answer 10

The best way to drop your database in Mongoose depends on which version of Mongoose you are using. If you are using a version of Mongoose that 4.6.4 or newer, then this method added in that release is likely going to work fine for you:

mongoose.connection.dropDatabase();

In older releases this method did not exist. Instead, you were to use a direct MongoDB call:

mongoose.connection.db.dropDatabase();

However, if this was run just after the database connection was created, it could possibly fail silently. This is related to the connection actually be asynchronous and not being set up yet when the command happens. This is not normally a problem for other Mongoose calls like .find(), which queue until the connection is open and then run.

If you look at the source code for the dropDatabase() shortcut that was added, you can see it was designed to solve this exact problem. It checks to see if the connection is open and ready. If so, it fires the command immediately. If not, it registers the command to run when the database connection has opened.

Some of the suggestions above recommend always putting your dropDatabase command in the open handler. But that only works in the case when the connection is not open yet.

Connection.prototype.dropDatabase = function(callback) {
  var Promise = PromiseProvider.get();
  var _this = this;
  var promise = new Promise.ES6(function(resolve, reject) {
    if (_this.readyState !== STATES.connected) {
      _this.on('open', function() {
        _this.db.dropDatabase(function(error) {
          if (error) {
            reject(error);
          } else {
            resolve();
          }
        });
      });
    } else {
      _this.db.dropDatabase(function(error) {
        if (error) {
          reject(error);
        } else {
          resolve();
        }
      });
    }
  });
  if (callback) {
    promise.then(function() { callback(); }, callback);
  }
  return promise;
};

Here's a simple version of the above logic that can be used with earlier Mongoose versions:

// This shim is backported from Mongoose 4.6.4 to reliably drop a database
// http://stackoverflow.com/a/42860208/254318
// The first arg should be "mongoose.connection"
function dropDatabase (connection, callback) {
    // readyState 1 === 'connected'
    if (connection.readyState !== 1) {
      connection.on('open', function() {
        connection.db.dropDatabase(callback);
      });
    } else {
      connection.db.dropDatabase(callback);
    }
}  

Answer 11

Mongoose 4.6.0+:

mongoose.connect('mongodb://localhost/mydb')
mongoose.connection.once('connected', () => {
    mongoose.connection.db.dropDatabase();
});

Passing a callback to connect won't work anymore:

TypeError: Cannot read property 'commandsTakeWriteConcern' of null

Answer 12

beforeEach((done) => {
      mongoose.connection.dropCollection('products',(error ,result) => {
      if (error) {
        console.log('Products Collection is not dropped')
      } else {
        console.log(result)
      }
    done()
    })
  })

Answer 13

To drop all documents in a collection:

await mongoose.connection.db.dropDatabase();

This answer is based off the mongoose index.d.ts file:

dropDatabase(): Promise<any>;

Answer 14

mongoose.connect(`mongodb://localhost/${dbname}`, {
        useNewUrlParser: true,
        useCreateIndex: true,
        useFindAndModify: true,
        useUnifiedTopology: true
    })
        .then((connection) => {
            mongoose.connection.db.dropDatabase();
        });

To delete a complete database, just pass the name... This one is working perfectly fine on version 4.4

Answer 15

Since the remove method is depreciated in the mongoose library we can use the deleteMany function with no parameters passed.

Model.deleteMany();

This will delete all content of this particular Model and your collection will be empty.

Answer 16

For dropping all documents in a collection:

myMongooseModel.collection.drop();

as seen in the tests