php第三章

//查看开启的方法
//echo phpinfo();
//单例
class A{
    private static $a = null;
    static function shareInstance()
    {
        if(self::$a == null)
        {
            self::$a = new self();
        }
        return self::$a;
    }
}

<?php
/**
 * Created by PhpStorm.
 * User: forr
 * Date: 15/9/20
 * Time: 12:23
 */
//连接数据库
try{
//$pdo = new PDO("mysql:host=localhost;dbname=forrdb;");//明文
//    $pdo = new PDO("uri:xxxx.ini");//读资源xxxx.ini配置文件
    $pdo = new PDO("mysqlpod");//在php.ini文件中配置dns
}catch(PODException $error){
    die("数据库连接失败".$error->getMessage());
}

// 执行查询
$sql = "select * from stu";
$stmt = $pdo->query($sql);
$list = $stmt->fetchAll(POD::FETCH_ASSOC);//返回带key的字典,非下标的
print_r($list);

//释放资源
$stmt = null;
$pdo = null;

//快捷查询
foreach($pod->query($sql) as $val)
{
    echo $val[‘id‘]."<br>";
}
//增加一行数据
$sql = "insert into stu values(null,‘boy‘,‘man‘,‘18‘)";
//删除行
$sql = "delete from stu where id = 6";
// 修改行
$sql = "update stu set name = ‘jobs‘ where id = 3";
$result = $pdo->exec($sql);
if($result)
{
    echo "成功执行";
}