Node.js MongoDB Ordina
Ordina il risultato
Utilizzare il sort()metodo per ordinare il risultato in ordine crescente o decrescente.
Il sort()metodo accetta un parametro, un oggetto che definisce l'ordinamento.
Esempio
Ordina il risultato in ordine alfabetico per nome:
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 mysort = { name: 1 };
dbo.collection("customers").find().sort(mysort).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
Salva il codice sopra in un file chiamato "demo_sort.js" ed esegui il file:
Esegui "demo_sort.js"
C:\Users\Your Name>node demo_sort.js
Che ti darà questo risultato:
[
{
_id: 58fdbf5c0ef8a50b4cdd9a86, name: 'Amy',
address: 'Apple st 652'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8e, name: 'Ben', address: 'Park Lane 38'},
{
_id: 58fdbf5c0ef8a50b4cdd9a8a,
name: 'Betty', address: 'Green Grass 1'},
{ _id: 58fdbf5c0ef8a50b4cdd9a90, name: 'Chuck', address:
'Main Road 989'},
{ _id: 58fdbf5c0ef8a50b4cdd9a87, name: 'Hannah', address:
'Mountain 21'},
{ _id:
58fdbf5c0ef8a50b4cdd9a84, name: 'John', address: 'Highway 71'},
{ _id: 58fdbf5c0ef8a50b4cdd9a88, name: 'Michael', address: 'Valley 345'},
{ _id:
58fdbf5c0ef8a50b4cdd9a85, name: 'Peter', address: 'Lowstreet 4'},
{ _id:
58fdbf5c0ef8a50b4cdd9a8b, name: 'Richard',
address: 'Sky st 331'},
{ _id: 58fdbf5c0ef8a50b4cdd9a89, name: 'Sandy', address: 'Ocean blvd 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8c, name: 'Susan', address: 'One way
98'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8d, name: 'Vicky', address: 'Yellow Garden 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a91, name: 'Viola', address: 'Sideway
1633'},
{
_id: 58fdbf5c0ef8a50b4cdd9a8f, name: 'William',
address: 'Central st 954'}
]
Ordine decrescente
Utilizzare il valore -1 nell'oggetto di ordinamento per ordinare in modo decrescente.
{ nome: 1 } // ascendente
{ nome: -1 } // discendente
Esempio
Ordina il risultato in ordine alfabetico per nome:
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 mysort = { name: -1 };
dbo.collection("customers").find().sort(mysort).toArray(function(err, result) {
if (err) throw err;
console.log(result);
db.close();
});
});
Salva il codice sopra in un file chiamato "demo_sort_desc.js" ed esegui il file:
Esegui "demo_sort_desc.js"
C:\Users\Your Name>node demo_sort_desc.js
Che ti darà questo risultato:
[
{
_id: 58fdbf5c0ef8a50b4cdd9a8f, name: 'William',
address: 'Central st 954'},
{ _id: 58fdbf5c0ef8a50b4cdd9a91, name: 'Viola', address: 'Sideway
1633'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8d, name: 'Vicky', address: 'Yellow Garden 2'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8c, name: 'Susan', address: 'One way
98'},
{ _id: 58fdbf5c0ef8a50b4cdd9a89, name: 'Sandy', address: 'Ocean blvd 2'},
{ _id:
58fdbf5c0ef8a50b4cdd9a8b, name: 'Richard',
address: 'Sky st 331'},
{ _id:
58fdbf5c0ef8a50b4cdd9a85, name: 'Peter', address: 'Lowstreet 4'},
{ _id: 58fdbf5c0ef8a50b4cdd9a88, name: 'Michael', address: 'Valley 345'},
{ _id:
58fdbf5c0ef8a50b4cdd9a84, name: 'John', address: 'Highway 71'},
{ _id: 58fdbf5c0ef8a50b4cdd9a87, name: 'Hannah', address:
'Mountain 21'},
{ _id: 58fdbf5c0ef8a50b4cdd9a90, name: 'Chuck', address:
'Main Road 989'},
{
_id: 58fdbf5c0ef8a50b4cdd9a8a,
name: 'Betty', address: 'Green Grass 1'},
{ _id: 58fdbf5c0ef8a50b4cdd9a8e, name: 'Ben', address: 'Park Lane 38'},
{
_id: 58fdbf5c0ef8a50b4cdd9a86, name: 'Amy',
address: 'Apple st 652'}
]