在课堂上使用 PDO [英] Use of PDO in classes

问题描述

我有几个类可以执行一些 MySQL 查询和准备好的语句.但是，我不知道如何将我的 PDO 对象合并到这些类中.例如，我想做这样的事情:

I have a few classes that perform some MySQL queries and prepared statements. However, I am lost in how to incorporate my PDO object within those classes. For example, I want to do something like this:

<?php

$dbh = new PDO(...);

class Foo extends PDO {
    public $dbh;

    public function bar() {
        $this->dbh->prepare('SELECT * FROM table');
        $this->dbh->execute();

    }
}


?>

不幸的是，它不起作用.谁能建议一种优雅的方法来做到这一点?谢谢你的时间.抱歉，我是新手，如果您有任何不清楚的地方，请留下任何评论，我会尽力回复！

Unfortunately, it doesn't work. Can anyone suggest an elegant way to do this? Thanks for your time. Sorry I'm new to this, please leave any comments if you are unclear about anything and I'll do my best to respond!

推荐答案

您可以在实现单例模式的类中实例化与数据库的连接.连接将完成一次，您的所有其他对象/脚本都可以轻松访问此类.

You can instantiate your connection to the database in a class that implement the singleton pattern. The connection will be done once and this class will be easily accessible by all of your other objects / scripts.

我在下面的例子中使用了一个叫做Core"的类；

i use a class called "Core" in the following example;

class Core
{
    public $dbh; // handle of the db connexion
    private static $instance;

    private function __construct()
    {
        // building data source name from config
        $dsn = 'pgsql:host=' . Config::read('db.host') .
               ';dbname='    . Config::read('db.basename') .
               ';port='      . Config::read('db.port') .
               ';connect_timeout=15';
        // getting DB user from config                
        $user = Config::read('db.user');
        // getting DB password from config                
        $password = Config::read('db.password');

        $this->dbh = new PDO($dsn, $user, $password);
    }

    public static function getInstance()
    {
        if (!isset(self::$instance))
        {
            $object = __CLASS__;
            self::$instance = new $object;
        }
        return self::$instance;
    }

    // others global functions
}

此类从名为Config"的静态类中获取参数，您可以在其中存储配置:

this class take parameters from a static class called "Config" where you can store your configuration:

<?php
class Config
{
    static $confArray;

    public static function read($name)
    {
        return self::$confArray[$name];
    }

    public static function write($name, $value)
    {
        self::$confArray[$name] = $value;
    }

}

// db
Config::write('db.host', '127.0.0.1');
Config::write('db.port', '5432');
Config::write('db.basename', 'mydb');
Config::write('db.user', 'myuser');
Config::write('db.password', 'mypassword');

在你所有的脚本/对象中，你只需要获取 Core 的实例，然后查询数据库

in all your scripts / objects you just have to get the instance of Core and then query the DB

$sql = "select login, email from users where id = :id";

try {
    $core = Core::getInstance();
    $stmt = $core->dbh->prepare($sql);
    $stmt->bindParam(':id', $this->id, PDO::PARAM_INT);

    if ($stmt->execute()) {
        $o = $stmt->fetch(PDO::FETCH_OBJ);
        // blablabla....

如果您需要有关单例的更多信息，请查看 PHP 文档 http://php.net/manual/en/language.oop5.patterns.php

If you need more information about singleton look at the PHP doc http://php.net/manual/en/language.oop5.patterns.php

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