Java JDBC and Database Connectivity

Java Application → JDBC API → JDBC Driver → Database (MySQL)

import java.sql.*;

public class DatabaseDemo {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/school_db";
        String user = "root";
        String password = "";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            System.out.println("Connected to MySQL successfully!");
        } catch (SQLException e) {
            System.out.println("Connection failed: " + e.getMessage());
        }
    }
}

String sql = "INSERT INTO students (name, age, grade) VALUES (?, ?, ?)";
try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
    pstmt.setString(1, "Alice");
    pstmt.setInt(2, 20);
    pstmt.setString(3, "A");
    int rows = pstmt.executeUpdate();
    System.out.println(rows + " row(s) inserted.");
}

String sql = "SELECT * FROM students";
try (Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery(sql)) {
    while (rs.next()) {
        System.out.printf("ID: %d, Name: %s, Age: %d, Grade: %s%n",
            rs.getInt("id"), rs.getString("name"),
            rs.getInt("age"), rs.getString("grade"));
    }
}

String sql = "UPDATE students SET grade = ? WHERE name = ?";
try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
    pstmt.setString(1, "A+");
    pstmt.setString(2, "Alice");
    pstmt.executeUpdate();
}

String sql = "DELETE FROM students WHERE id = ?";
try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
    pstmt.setInt(1, 5);
    pstmt.executeUpdate();
}

import java.sql.*;
import java.util.Scanner;

public class StudentDB {
    static final String URL = "jdbc:mysql://localhost:3306/school_db";

    public static void main(String[] args) throws SQLException {
        Connection conn = DriverManager.getConnection(URL, "root", "");
        Scanner sc = new Scanner(System.in);

        System.out.println("=== STUDENT DATABASE ===");
        System.out.println("1. Add Student  2. View All  3. Search  4. Delete  5. Exit");

        boolean running = true;
        while (running) {
            System.out.print("\nChoice: ");
            int choice = sc.nextInt(); sc.nextLine();
            switch (choice) {
                case 1:
                    System.out.print("Name: "); String name = sc.nextLine();
                    System.out.print("Age: "); int age = sc.nextInt();
                    sc.nextLine();
                    System.out.print("Grade: "); String grade = sc.nextLine();
                    PreparedStatement ps = conn.prepareStatement(
                        "INSERT INTO students (name, age, grade) VALUES (?, ?, ?)");
                    ps.setString(1, name); ps.setInt(2, age); ps.setString(3, grade);
                    ps.executeUpdate();
                    System.out.println("Student added!");
                    break;
                case 2:
                    ResultSet rs = conn.createStatement().executeQuery("SELECT * FROM students");
                    while (rs.next()) {
                        System.out.printf("%d | %s | %d | %s%n",
                            rs.getInt("id"), rs.getString("name"),
                            rs.getInt("age"), rs.getString("grade"));
                    }
                    break;
                case 5: running = false; break;
            }
        }
        conn.close();
        sc.close();
    }
}