const { MongoClient } = require('mongodb');

const url = 'mongodb://127.0.0.1:27017';
const dbName = 'college';
const client = new MongoClient(url);

async function run() {
  try {
    await client.connect();
    console.log("✅ Connected to MongoDB");

    const db = client.db(dbName);
    const students = db.collection('Students');

    // CREATE
    await students.insertMany([
      { name: 'John', rollNo: 101, section: 'A', gpa: 3.7 },
      { name: 'Emma', rollNo: 102, section: 'B', gpa: 3.9 },
    ]);
    console.log("📝 Students inserted.");

    // READ
    const allStudents = await students.find().toArray();
    console.log("📄 All Students:", allStudents);

    // UPDATE
    await students.updateOne({ rollNo: 101 }, { $set: { gpa: 3.8 } });
    console.log("🔧 GPA updated for Roll No 101.");

    // DELETE
    await students.deleteOne({ rollNo: 102 });
    console.log("🗑️ Student with Roll No 102 deleted.");
    
  } finally {
    await client.close();
    console.log("🔒 Connection closed.");
  }
}

run().catch(console.error);