<?php

// 共同接口
interface db
{
    function conn();
}

class dbmysql implements db
{
    public function conn()
    {
        echo '连接上了MySQL';
    }
}

class dbsqlite implements db
{
    public function conn()
    {
        echo '连接上了sqlite';
    }
}

//// 客户端 不知道dbmysql 和 dbsqlite 的内部细节，只知道实现了db接口
//$db = new dbmysql();
//$db->conn();

class Factory
{

    public static function createDB($type)
    {
        if ($type == 'mysql') {
            return new  dbmysql();
        } elseif ($type == 'sqlite') {
            return new dbsqlite();
        } else {
            throw new \Exception('Error db type', 1);
        }
    }
}


// 客户端 现在不知道服务端到底有那些类
$mysql = Factory::createDB('mysql');
$mysql->conn();

$mysql = Factory::createDB('sqlite');
$mysql->conn();

$mysql = Factory::createDB('oracle');
$mysql->conn();