php class类 PDO连接数据，增删查改

1、数据库连接

class Db{
    public $dns;
    public $user;
    public $password;
    public $pdo;
    function __construct($dns,$user,$password){
        $this->dns = $dns;
        $this->user = $user;
        $this->password = $password;
        //连接数据库
        $this->content();
    }
    function content(){
        $this->pdo = new PDO($this->dns,$this->user,$this->password);
    }
    function __destruct(){
        $this->pdo = null;
        echo '执行完毕，关闭连接';
    }
}
$db = new Db('mysql:host=locaohost;dbname=film', 'root', 'root');
print_r($db->pdo); //结果为PDO Object ( ) ，连接数据库成功

2、查询

$stmt = $db->pdo->prepare('SELECT * FROM `user` WHERE `id`>=:id');
$stmt -> execute(['id'=>1]);
$stmt -> setFetchMode(PDO::FETCH_ASSOC);
while( $user = $stmt->fetch() ){
    print_r($user);
}
===================
print_r( $stmt->fetchAll() ); //或者全部调用

3、新增

$stmt = $db->pdo->prepare('INSERT `user`(name,tel,password) VALUES(:name,:tel,:password)');
$stmt -> execute(['name'=>张明朗, 'tel'=>18080809999, 'password'=>sha1(123456)]);

4、更改

$stmt = $db->pdo->prepare('UPDATE `user` SET `name`=:name, `tel`=:tel WHERE `id`=:id');
$stmt -> execute(['id'=>9,'name'=>'张明轩','tel'=>19980807777]);

5、删除

$stmt = $db->pdo->prepare('DELECT FROM `user` WHERE `id`=:id ');
$stmt->execute(['id'=12]);