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When finding documents in a collection, you can filter the result by using a query object.
method is a query object, and is used to limit the search.
Find documents with the address "Park Lane 38":
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 query = { address: "Park Lane 38" };
dbo.collection("customers").find(query
).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
Save the code above in a file called "demo_mongodb_query.js" and run the file:
Run "demo_mongodb_query.js"C:\Users\
>node demo_mongodb_query.js Which will give you this result: [
{ _id: 58fdbf5c0ef8a50b4cdd9a8e, name: 'Ben', address: 'Park Lane 38' }]
You can write regular expressions to find exactly what you are searching for. Regular expressions can only be used to query strings. To find only the documents where the "address" field starts with the letter "S", use the regular expression /^S/
Find documents where the address starts with the letter "S":
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 query = { address:/^S/
};
dbo.collection("customers").find(query).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
Save the code above in a file called "demo_mongodb_query_s.js" and run the file:
Run "demo_mongodb_query_s.js"C:\Users\
>node demo_mongodb_query_s.js Which will give you this result: [
{ _id:
58fdbf5c0ef8a50b4cdd9a8b , name: 'Richard', address: 'Sky st 331' },
{ _id: 58fdbf5c0ef8a50b4cdd9a91 , name: 'Viola', address: 'Sideway
1633' }]