Update Document
You can update a record, or document as it is called in MongoDB, by using the updateOne() method.
The first parameter of the updateOne() method is a query object defining which document to update.
Note
If the query finds more than one record, only the first occurrence is updated.
The second parameter is an object defining the new values of the document.
Example
Update the document with the address "Valley 345" to name="Mickey" and address="Canyon 123":
let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://127.0.0.1:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
let dbo = db.db("mydb");
let myquery = { address: "Valley 345" };
let newvalues = {
$set: {name: "Mickey", address: "Canyon 123" } };
dbo.collection("customers").updateOne(myquery, newvalues, function(err, res) {
if (err) throw err;
console.log("1 document updated");
db.close();
});
});Save the code above in a file called "demo_update_one.js" and run the file:
Run "demo_update_one.js"
C:\Users\
Your Name
>node demo_update_one.jsWhich will give you this result
1 document updatedUpdate Only Specific Fields
When using the $set operator, only the specified fields are updated:
Example
Update the address from "Valley 345" to "Canyon 123":
...
let myquery = { address: "Valley 345" };
let newvalues = {
$set: { address: "Canyon 123" }
};
dbo.collection("customers").updateOne(myquery, newvalues, function(err, res) { ...Update Many Documents
To update all documents that meets the criteria of the query, use the updateMany() method.
Example
Update all documents where the name starts with the letter "S":
let MongoClient = require('mongodb').MongoClient;
let url = "mongodb://127.0.0.1:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
let dbo = db.db("mydb");
let myquery = { address: /^S/ };
let newvalues = {$set: {name: "Minnie"} };
dbo.collection("customers").updateMany(myquery, newvalues, function(err, res) {
if (err) throw err;
console.log(res.result.nModified + " document(s) updated");
db.close();
});
});Save the code above in a file called "demo_update_many.js" and run the file:
Run "demo_update_many.js"
C:\Users\
Your Name
>node demo_update_many.jsWhich will give you this result
2 document(s) updatedThe Result Object
The updateOne() and the updateMany() methods return 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: 1, nModified: 2, ok: 1 }You can use this object to return the number of updated documents:
Return the number of updated documents
console.log(res.result.nModified);Which will produce this result
2