在课堂上使用PDO [英] Use of PDO in classes

问题描述

我有一些类可以执行一些MySQL查询和准备好的语句.但是，我不知道如何在这些类中合并我的PDO对象.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，如果您不清楚任何事情，请留下任何评论，我会尽力答复！

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，所有其他对象/脚本都可以轻松访问该类.

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.

在下面的示例中，我使用名为"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
}

该类从名为"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');

在所有脚本/对象中，您只需要获取Core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

这篇关于在课堂上使用PDO的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！