PHP sample code to update database in batches

/**
* Batch update database
* by bbs.it-home.org
*/
for($i=1;$i<=$this->size;$i++){
 $query[]="update tb_enterprise set eid='$eidex[$i]' where eid=$i";
  }
  $query_string=implode(";", $query);
  $query_result=$db->multi_query($query);
  if($query_result){
   echo "Successed to update data!";
  }else{
   echo "Failed to update data!";
  }