//SQL:
CREATE TABLE Users (
    id INT PRIMARY KEY AUTO_INCREMENT,
    username VARCHAR(50) NOT NULL,
    password VARCHAR(50) NOT NULL,
    email VARCHAR(100) NOT NULL
);

//INSERT
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

public class InsertUser {
    private static final String INSERT_USER_SQL = "INSERT INTO Users (username, password, email) VALUES (?, ?, ?)";

    public static void main(String[] args) {
        try (Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "root", "password");
             PreparedStatement preparedStatement = connection.prepareStatement(INSERT_USER_SQL)) {

            preparedStatement.setString(1, "john_doe");
            preparedStatement.setString(2, "securepassword");
            preparedStatement.setString(3, "john@example.com");

            int rowsAffected = preparedStatement.executeUpdate();
            System.out.println(rowsAffected + " row(s) inserted.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

//SELECT
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class SelectUsers {
    private static final String SELECT_ALL_USERS_SQL = "SELECT * FROM Users";

    public static void main(String[] args) {
        try (Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "root", "password");
             PreparedStatement preparedStatement = connection.prepareStatement(SELECT_ALL_USERS_SQL);
             ResultSet resultSet = preparedStatement.executeQuery()) {

            while (resultSet.next()) {
                System.out.println("ID: " + resultSet.getInt("id") +
                                   ", Username: " + resultSet.getString("username") +
                                   ", Email: " + resultSet.getString("email"));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

//UPDATE
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;

public class UpdateUserEmail {
    private static final String UPDATE_EMAIL_SQL = "UPDATE Users SET email = ? WHERE username = ?";

    public static void main(String[] args) {
        try (Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "root", "password");
             PreparedStatement preparedStatement = connection.prepareStatement(UPDATE_EMAIL_SQL)) {

            preparedStatement.setString(1, "new_email@example.com");
            preparedStatement.setString(2, "john_doe");

            int rowsAffected = preparedStatement.executeUpdate();
            System.out.println(rowsAffected + " row(s) updated.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

//OUTPUT:
ID: 1, Username: john_doe, Email: john@example.com