Recursive array correct method of display

Question

Sorry guys back again with my recursive array which does work but I cannot get the "layout" right what I am after is a "proper" tree structure using <ul>,<li> so you end up like this:

Item
- Child
  - Child of child
    - Etc...

My function looks like this - whilst the function works the "layout" does not suggestions please.

function recursive_array($results,$tbl) {
global $DBH;
$tbl = $tbl;
if (count($results)) {
    foreach($results as $res) {
        if( $res->ParentID == 0 ) { 
        echo '<ul class="recursive">';
        echo '<li>';    
        echo $res->Name;
        echo $res->Description;
        echo $res->date_added;
        echo '<ul>'; 
        }

        if( $res->ParentID != 0 ) { 
        echo '<li>';
             echo $res->Name;
             echo $res->Description;
             echo $res->date_added;
        echo '</li>';
        }


        $STH = $DBH->query("SELECT * FROM ".$tbl." WHERE ParentID  = '".$res->ID."'");
        $fquerycount = $STH->rowCount();
        $STH->setFetchMode(PDO::FETCH_OBJ);
        recursive_array($STH,$tbl);
        if( $res->ParentID == 0 ) { 
        echo '</ul></li></ul>';
        }       
    }
}
}

cwallenpoole · Accepted Answer · 2011-09-02 10:16:18Z

1

I am really not a fan of recursive SQL. I've used it, it works, but it always struck me as... yeck...

How about this instead: create a topicID (some sort of selector which will include all of the items which you would eventually like to have output) and select based on that, ordered by parentID.

SELECT * FROM $tbl WHERE topicID = 1 ORDER BY parentID;

Then, you organize like this:

$output = array();
$currentParent = -1;
while( $row = $stmt->fetch(PDO::FETCH_OBJ) )
{ 
    if( $currentParent != $row->ParentID )
    {
        $currentParent = $row->ParentID;
        $output[ $currentParent ] = array();
    }
    $output[ $currentParent ][] = $row;
}

function outputLists( array $current, array $output )
{
    echo '<ul>';
    foreach( $current as $res )
    {
        echo '<li>';
        echo $res->Name;
        echo $res->Description;
        echo $res->date_added;
        // if it is set, clearly we have a node to traverse
        if( isset( $output[ $res->ID ] ) )
             // seed the next call to the function with the new 
             // node value (found in output) and it will create
             // the appropriate ul and li tags
             outputLists( $output[ $res->ID ], $output );
        echo '</li>';
    }
    echo '</ul>';
}
// start with the group with parentID = 0
outputLists( $output[ 0 ], $output );

So, instead of having recursive SQL, you have one output from the database creating a tree-like structure in PHP.

edited Sep 2, 2011 at 10:16

answered Sep 2, 2011 at 8:52

cwallenpoole

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1 Comment

Russell Parrott Over a year ago

Perfect! I agree about recursive arrays also but ... sometimes useful

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