PseudoUserStats.php

private $_uid;
private $_rows = [];

public function __constructor($uid) {
  $_uid = $uid;
}

public function load() {
   $records = DB::table("user_stats")->where("uid",$this->_uid)->getAll()
   foreach ($records as $rec) {
      $class = "UserStatGeneric";
      switch ($rec->name) {
         case "stamina":
           $class = "UserStatStamina";
           break;
      }
      $obj = new $class($rec);
      $this->_rows[$rec->name] = $obj;
   }
}

public function save() {
  $values = [];
  foreach ($this->_rows as $name => $obj) {
    $queryValue = "(1001, 123456, 'stamina', 100)"; // generate mysql-safe CSV update block, this is an example
  }
  $query = "replace into user_stats values ".implode(',', $values).";";
  DB::doMeRaw($query);
}

public function add($name, $amount) {
  if (isset($this->_rows[$name])) {
    $this->_rows[$name]->add($amount);
  }
}

// run every N minutes for automatically modified items
public function updatePoll() {
  foreach ($this->_rows as $name => $obj) {
    $obj->updatePoll();
  }
}