как вносить значения в таблицу ?

$rsinfoUser = CUser::GetByID($_POST["userId"]);

$user = new CUser;

$aFields;

                while($arinfoUser = $rsinfoUser->Fetch())

               {   

                  $i=0;

                  foreach ($arinfoUser[UF_PLAN] as $explodestring)

                  {

                     $pieces0 = explode('a:2:{s:8:"exercise";s:', $explodestring);

                     $pieces1 = explode('";}', $pieces0[1]);

                     $pieces2 = explode('";s:4:"date";s:10:"', $pieces1[0]);

                     $pieces = preg_split('/^[0-9]+:"/', $pieces2[0]);

                        if ($pieces2[1]==$date)

                        {   $ab=$i;

                           

                                  $UF_PLAN[$ab] = array(         

                                        'exercise'=>$a,

                                        'date'=>$pieces2[1],

                                 );

                        }

                        else 

                        { //echo $i;

                           $ab=$i;

                           $UF_PLAN[$ab] = array(

                                        'exercise'=>$pieces[1],

                                        'date'=>$pieces2[1],

                                  );

                        }

                        ++$i;

                        

                  }

                  $aFields= array('UF_PLAN' => $UF_PLAN);

               }

                  

$user->Update($_POST["userId"], $aFields);