sql如何连接数据库服务器

mysql -h hostname -P port -u username -p

import mysql.connector

mydb = mysql.connector.connect(
  host="hostname",
  user="username",
  password="password",
  database="database_name"
)

print(mydb)

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DatabaseConnector {
    public static void main(String[] args) {
        String url = "jdbc:mysql://hostname:port/database_name";
        String user = "username";
        String password = "password";

        try {
            Connection connection = DriverManager.getConnection(url, user, password);
            System.out.println("Connected to the database!");
        } catch (SQLException e) {
            System.out.println("Failed to connect to the database!");
            e.printStackTrace();
        }
    }
}

const mysql = require('mysql');

const connection = mysql.createConnection({
  host: 'hostname',
  user: 'username',
  password: 'password',
  database: 'database_name'
});

connection.connect((err) => {
  if (err) throw err;
  console.log('Connected to the database!');
});