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To delete a record, or document as it is called in MongoDB, we use the deleteOne() method.
method is a query object defining which document to delete.
If the query finds more than one document, only the first occurrence is deleted.
Delete the document with the address "Mountain 21":
let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
let dbo = db.db("mydb");
let 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:\Users\
>node demo_delete.js Which will give you this result: 1 document deleted
To delete more than one document, use the deleteMany() method.
method is a query object defining which documents to delete.
Delete all documents were the address starts with the letter "O":
let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
let dbo = db.db("mydb");
let 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:\Users\
>node demo_delete_many.js Which will give you this result: 2 document(s) deleted
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:
Return the number of deleted documents:
console.log(obj.result.n);