class usermodel{

protected $email='user@163.com';

protected $data=array();

public function __set($k,$v){

$this->data[$k]=$v; //放在一个数组里

}

public function add(){

$sql='insert into table (';

$sql.=implode(',',array_keys($this->data));

$sql.=') values(\'';

$sql.=implode("','",array_values($this->data));

$sql.="')";

return $sql;

}

}

$user=new usermodel();

$user->username='lisi';

$user->email='lisi@163.com';

echo $user->add();

//insert
into table (username,email)
values('lisi','lisi@163.com')