Flash cards
Review the key moves
What is the main idea behind Node.js MongoDB Limit?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
[ { ___: 58fdbf5c0ef8a50b4cdd9a84 , name: 'John', address: 'Highway 71'}, { _id: 58fdbf5c0ef8a50b4cdd9a85 , name: 'Peter', address: 'Lowstreet 4'}, {Put the learning moves in the order that makes the concept easiest to apply.
Limit the Result
To limit the result in MongoDB, we use the limit() method.
The limit() method takes one parameter, a number defining how many documents to return.
Consider you have a "customers" collection:
customers
[ { _id: 58fdbf5c0ef8a50b4cdd9a84 , name: 'John', address: 'Highway 71'}, { _id: 58fdbf5c0ef8a50b4cdd9a85 , name: 'Peter', address: 'Lowstreet 4'}, {
_id: 58fdbf5c0ef8a50b4cdd9a86 , name: 'Amy', address: 'Apple st 652'}, { _id: 58fdbf5c0ef8a50b4cdd9a87 , name: 'Hannah', address: 'Mountain 21'}, { _id: 58fdbf5c0ef8a50b4cdd9a88 , name: 'Michael', address: 'Valley 345'},
{ _id: 58fdbf5c0ef8a50b4cdd9a89 , name: 'Sandy', address: 'Ocean blvd 2'}, {
_id: 58fdbf5c0ef8a50b4cdd9a8a , name: 'Betty', address: 'Green Grass 1'}, { _id: 58fdbf5c0ef8a50b4cdd9a8b , name: 'Richard', address: 'Sky st 331'}, { _id: 58fdbf5c0ef8a50b4cdd9a8c , name: 'Susan', address: 'One way 98'}, { _id: 58fdbf5c0ef8a50b4cdd9a8d , name: 'Vicky', address: 'Yellow Garden 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8e , name: 'Ben', address: 'Park Lane 38'}, {
_id: 58fdbf5c0ef8a50b4cdd9a8f , name: 'William', address: 'Central st 954'}, { _id: 58fdbf5c0ef8a50b4cdd9a90 , name: 'Chuck', address: 'Main Road 989'}, { _id: 58fdbf5c0ef8a50b4cdd9a91 , name: 'Viola', address: 'Sideway 1633'}
]Example
Limit the result to only return 5 documents:
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");
dbo.collection("customers").find() .limit(5) .toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});Save the code above in a file called "demo_mongodb_limit.js" and run the file:
Run "demo_mongodb_limit.js"
C:\Users\
Your Name
>node demo_mongodb_limit.jscustomers
[ { _id: 58fdbf5c0ef8a50b4cdd9a84 , name: 'John', address: 'Highway 71'}, { _id: 58fdbf5c0ef8a50b4cdd9a85 , name: 'Peter', address: 'Lowstreet 4'}, {
_id: 58fdbf5c0ef8a50b4cdd9a86 , name: 'Amy', address: 'Apple st 652'}, { _id: 58fdbf5c0ef8a50b4cdd9a87 , name: 'Hannah', address: 'Mountain 21'}, { _id: 58fdbf5c0ef8a50b4cdd9a88 , name: 'Michael', address: 'Valley 345'}
]As you can see from the result above, only the 5 first documents were returned.