DB类中的连接PHP

Question

什么是在类中使数据库连接可用的最快和最简单的方法，以便类中的所有公共函数都可以访问它，以及如何在函数内部调用它？

Answer 1

将连接句柄保存为类变量。

class Test 
{ 
    public $dbh; 

    public function connect($host,$username,$password,$dbname) 
    { 
      $this->dbh = mysql_connect($host,$username,$password); //Of course, you'd want to do some actual error checking. Also, you can have a separate function for selecting the DB if you need to use multiple databases 
      mysql_select_db($dbname,$this->dbh); //You use $this->variable to refer to the connection handle 
    } 

    public function query($sql) 
    { 
     return mysql_query($sql,$this->dbh); 
    } 
} 

Answer 2

或者你可以使用类的__construct（）方法，每当一个新的对象初始化它被自动调用..

class MySQLDatabase { 
    private $connection; 
    function __construct() { 
     $this->open_connection(); 
    } 
    public function open_connection() { 
     $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS); 
     if (!$this->connection) { 
      die("Database connection failed: " . mysql_error()); 
     } else { 
      $db_select = mysql_select_db(DB_NAME, $this->connection); 
      if (!$db_select) { 
       die("Database selection failed: " . mysql_error()); 
      } 
     } 
    } 
    public function query($sql) { 
     $result = mysql_query($sql, $this->connection); 
     return $result; 
    } 
}