dtr87341 2016-04-13 12:23
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PHP - 最佳实践类中的全局数据库变量(OOP)[重复]

What is 'best practice' regarding accessing the database when you have multiple classes with methods that do queries?

Global $db variable:

$db = new mysqli('localhost', 'my_user', 'my_password', 'my_db');

class Item {
    private $id;

    function __construct($id) {
        $this->id = $id;
    }

    public function remove() {
        global $db;

        // queries and stuff.
    }
}

Or maybe, passing the $db to the constructor?

$db = new mysqli('localhost', 'my_user', 'my_password', 'my_db');

$item = new Item(5,$db);

class Item {
    private $id;
    protected $db;

    function __construct($id,$db) {
        $this->id = $id;
        $this->id = $db;
    }

    public function remove() {
        // queries and stuff.
    }
}

Or maybe another way is better than both of these?

</div>
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2条回答 默认 最新

  • drzil26260 2016-04-13 12:34
    关注

    For global objects which can potentially be used anywhere I personally prefer singleton classes:

    class DBConnection {
    
         private static $instance = null;
    
         private $db;
         private function __construct() {
             $this->db = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
         }
    
         public static function getDB() {
               if (self::$instance === null) { 
                   self::$instance = new self();
               }
               return self::$instance->db;
         }    
    }
    

    This way you can just call: DBConnection::getDB() anywhere you need to, and this can also work with auto-loading.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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