有什么建议可以改进我的 PDO 连接类吗？

Question

我对 pdo 很陌生，所以我基本上只是使用我正在阅读的介绍性书籍中的信息组合了一个简单的连接类。但是这种连接有效吗？如果有人有任何有用的建议，我将不胜感激。

class PDOConnectionFactory{

    public $con = null;
    // swich database?
    public $dbType  = "mysql";
    
    // connection parameters

    public $host    = "localhost";
    public $user    = "user";
    public $senha   = "password";
    public $db  = "database";
    

    public $persistent = false;
    
    // new PDOConnectionFactory( true ) <--- persistent connection
    // new PDOConnectionFactory()       <--- no persistent connection
    public function PDOConnectionFactory( $persistent=false ){
        // it verifies the persistence of the connection
        if( $persistent != false){ $this->persistent = true; }
    }
    
    public function getConnection(){
            try{
                $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, 
                array( PDO::ATTR_PERSISTENT => $this->persistent ) );
                // carried through successfully, it returns connected
                return $this->con;
            // in case that an error occurs, it returns the error;
            }catch ( PDOException $ex ){  echo "We are currently experiencing technical difficulties.  ".$ex->getMessage(); }

    }
    
    // close connection
    public function Close(){
        if( $this->con != null )
            $this->con = null;
    }
}

Answer 1

在实现“工厂”时，通常使用它的其他类、方法等不必知道或关心连接、用户名、密码等。

我会做的更像是：

static class PDOConnectionFactory {
    // database
    private $dbType = "mysql";

    // connection parameters
    private $host = "localhost";
    private $user = "user";
    private $senha = "password";
    private $db = "database";

    // new CreateNewConnection( true ) <--- persistent connection
    // new CreateNewConnection()       <--- no persistent connection
    public function CreateNewConnection($persistent = false) {
        try {
            $con = new PDO($dbType . ":host=" . $host . ";dbname=" . $db, $user, $senha, array(PDO::ATTR_PERSISTENT => $persistent));
            // carried through successfully, it returns connected
            return $con;
        }
        catch (PDOException $ex) {
            // in case that an error occurs, it returns the error;
            echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: " . $ex->getMessage();
        }
    }
}

然后你可以以任何你需要的方式使用 CreateNewConnection() 返回的连接。

我没有检查上面的代码是否编译，可能有一些错别字/问题，但你明白了。现在你需要更进一步，实现类似于存储库模式的东西:)

Answer 2

我的建议是您实现一个单例以将 PDO 的实例化限制为一个对象。它可能看起来像这样：

class Database {

    protected static $_instance;
    protected $_connection;
    protected $_dns = 'mysql:host=localhost;dbname=mydbname';
    protected $_username = 'myusername';
    protected $_password = 'mypassword';

    /**
    * Singleton pattern implementation makes "new" unavailable
    */
    protected function __construct()
    {
        $this->_connection = 
            new PDO($this->_dns, $this->_username, $this->_password);
    }

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

    public static function getInstance()
    {
        if (null === self::$_instance) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    /**
    * Singleton pattern implementation makes "clone" unavailable
    */
    protected function __clone()
    {}
}


$dbc = Database::getInstance()->getConnection();