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Delete Document

To delete a record, or document as it is called in MongoDB, we use the deleteOne() method.

The first parameter of the deleteOne() method is a query object defining which document to delete.

Note: If the query finds more than one document, only the first occurrence is deleted.

Example

Delete the document with the address "Mountain 21":

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  var dbo = db.db("mydb");
  var myquery = { address: 'Mountain 21' };
  dbo.collection("customers").deleteOne(myquery, function(err, obj) {
    if (err) throw err;
    console.log("1 document deleted");
    db.close();
  });
});

Save the code above in a file called "demo_delete.js" and run the file:

Run "demo_delete.js"

C:UsersYour Name>node demo_delete.js

Which will give you this result:

1 document deleted

Delete Many

To delete more than one document, use the deleteMany() method.

The first parameter of the deleteMany() method is a query object defining which documents to delete.

Example

Delete all documents were the address starts with the letter "O":

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  var dbo = db.db("mydb");
  var myquery = { address: /^O/ };
  dbo.collection("customers").deleteMany(myquery, function(err, obj) {
    if (err) throw err;
    console.log(obj.result.n + " document(s) deleted");
    db.close();
  });
});

Save the code above in a file called "demo_delete_many.js" and run the file:

Run "demo_delete_many.js"

C:UsersYour Name>node demo_delete_many.js

Which will give you this result:

2 document(s) deleted

The Result Object

The deleteMany() method returns an object which contains information about how the execution affected the database.

Most of the information is not important to understand, but one object inside the object is called "result" which tells us if the execution went OK, and how many documents were affected.

The result object looks like this:

{ n: 2, ok: 1 }

You can use this object to return the number of deleted documents:

Example

Return the number of deleted documents:

console.log(obj.result.n);

Which will produce this result:

2
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