怎样连接mysql数据库代码

import mysql.connector

config = {
    'user': 'your_username',
    'password': 'your_password',
    'host': 'your_host',
    'database': 'your_database'
}

try:
    conn = mysql.connector.connect(**config)
    print("Connected to MySQL database")
    # Perform database operations here
except mysql.connector.Error as error:
    print(f"Failed to connect to MySQL database: {error}")
finally:
    if conn.is_connected():
        conn.close()
        print("Disconnected from MySQL database")

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

public class Main {
    public static void main(String[] args) {
        String url = "jdbc:mysql://your_host/your_database";
        String username = "your_username";
        String password = "your_password";

        try {
            Connection conn = DriverManager.getConnection(url, username, password);
            System.out.println("Connected to MySQL database");
            // Perform database operations here
            conn.close();
            System.out.println("Disconnected from MySQL database");
        } catch (SQLException e) {
            System.out.println("Failed to connect to MySQL database: " + e.getMessage());
        }
    }
}

<?php
$servername = "your_host";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected to MySQL database\n";
    // Perform database operations here
    $conn = null;
    echo "Disconnected from MySQL database\n";
} catch(PDOException $e) {
    echo "Failed to connect to MySQL database: " . $e->getMessage();
}
?>

require 'mysql2'

client = Mysql2::Client.new(
    :host => "your_host",
    :username => "your_username",
    :password => "your_password",
    :database => "your_database"
)

begin
    puts "Connected to MySQL database"
    # Perform database operations here
ensure
    client.close
    puts "Disconnected from MySQL database"
end