الاستعلامات المعلَّمة

const express = require('express');const app = express();app.use(express.json());app.use(express.urlencoded({ extended: false })); const sqlite3 = require('sqlite3');const db = new sqlite3.Database(':memory:');db.serialize(() => {  db.run(`CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT, pass TEXT, role TEXT, email TEXT)`);  db.run(`INSERT INTO users (name, pass, role, email) VALUES    ('سارة', 's@rah123', 'customer', 'sara@mail.sa'),    ('خالد', 'kh@led456', 'customer', 'khaled@mail.sa'),    ('المدير', 'Adm!n#2025', 'admin', 'admin@mail.sa')`);  db.run(`CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT, price INTEGER)`);  db.run(`INSERT INTO products (name, price) VALUES    ('سماعة', 120), ('لوحة مفاتيح', 90), ('كاميرا ويب', 210)`);}); app.get('/products', (req, res) => {  // ✓ اسم العمود لا يُعلَّم؛ يُختار من قائمة مسموحة  const allowed = { price: 'price', name: 'name' };  const col = allowed[req.query.sort] || 'id';  const dir = req.query.dir === 'desc' ? 'DESC' : 'ASC';  db.all(`SELECT id, name, price FROM products ORDER BY ${col} ${dir}`, [], (e, rows) => res.json(rows));}); app.listen(3000);