Node.js MongoDB Delete
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();
});
});
Run example »
Save the code above in a file called "demo_delete.js" and run the file:
Run "demo_delete.js"
C:\Users\Your 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();
});
});
Run example »
Save the code above in a file called "demo_delete_many.js" and run the file:
Run "demo_delete_many.js"
C:\Users\Your 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
