php - 通过php连接mysql

Question

class DatabaseConnection{
  private $connection;
  private $username;
  private $password;
  private $serverName;
  private $database;
  private $database_found = false;

  //constructor with params
  public function __construct($database,$username,$password,$serverName){
    $this->$username = $username;
    $this->$password = $password;
    $this->$serverName = $serverName;
    $this->$database = $database;
  }

  //estabilish database connection
  public function connect()
  {
    $connection = mysql_connect($this->serverName,$this->username,$this->password);
    if($connection)
    {
      echo "Connection was successful!\n";
      $db = mysql_select_db($this->database,$connection);
      if($db)
      {
        echo "Database found!\n";
        $this->database_found = true;
      }
      else{
        echo "Database not found!\n";
      }
    }
    else {
      echo "Failed to connect to the database!\n";
    }
  }

  //closes connection
  public function close_connection(){
    mysql_close();
    echo "Connection closed!\n";
  }

  public function getConnection(){
    return $this->connection;
  }

  public function getDatabaseState(){
    return $this->database_found;
  }
}

这是我的数据库连接类。它连接到 mysql，但出于某种原因它不想连接到数据库(我尝试将数据库名称作为字符串插入 mysql_select_database 但仍然不起作用)。数据库存在原因它是手动创建的。感谢您的帮助。

Answer 1

mysql_* 函数已弃用，您应该使用 PDO . Here是我找到的第一个教程。

您还可以在应该使用 $this->username 的地方使用 $this->$username。这是 the official tutorial关于 PHP 类。

此外，约定是在类中编写私有(private)变量，并在开头加上下划线，如下所示:

• private $_username; 创建它;
• $this->_username 来调用它。

您还可以创建 getter 和 setter 来与您的变量交互。 ( why? )