Question

I have “Undefined offset” error in Yii framework, I need go to first id if next id is null and if last id if previous id is null?

public static function getNextOrPrevId($currentId, $nextOrPrev)
{
    $records=NULL;
    if($nextOrPrev == "prev")
       $order="id DESC";
    if($nextOrPrev == "next")
       $order="id ASC";

    $records=Photo::model()->findAll(
       array('select'=>'id', 'order'=>$order)
       );

    foreach($records as $i=>$r)
       if($r->id == $currentId)
          return $records[$i+1]->id ? $records[$i+1]->id : NULL;
    return NULL;
}

error line

return $records[$i+1]->id ? $records[$i+1]->id : NULL;

Answer 1

return isset($records[$i+1]) ? $records[$i+1]->id : NULL;

But really, you should directly select the next id from the database, not select all ids and loop through them one by one in PHP.

$record = Photo::model()->findAll(array(
    'select' => 'id',
    'order'  => $order,
    'where'  => "id > $currentId",
    'limit'  => 1
));

(I don’t know Yii, so I’m just making the syntax up. You get the idea though.)