How I implimented a "Nested Treeview" with a table

I wanted to represent a network map in a table.. which consists of how our various datacenters/sites/customers are linked. Not sure if this is the best way to do it, but it works. (open to suggestions!)

The the relationships are stored as simple linked-list in the database:

Each site is assigned a "tree_sort" ID so they can be sorted into position...

Screen Shot 2023-04-20 at 9.14.52 AM

So in RETOOL SQL query:

       select * from netsites 
           order by tree_sort ASC;

Add a Transformer to the Query to create the "nesting indents":

// Add NESTING Lines/Indentations to to names
return formatDataAsArray(data).map(row=>{
  var n='';
  let indent='   ';
      n+='<span style="color:#ddd;">';
      if(row.tree_level>2){   // if more than 1 indent, add vertical bars
        let indent2=indent+'|'+indent;
      // now add the vert bar with horiz bar ie.  |--
      n += indent + '|&#8212; </span>' 
  n += '<b>' + '</b> &nbsp; <span style="color:#ccc;">#'+row.netsite_id+'</span>';
  return row;

which adds these:

Here's the code in PHP Backend which creates the tree_sort ID from the Linked-List relationship

    public function calcTreeSort(){

        // first reset all sites to the bottom of list (ie 999)
        $this->dbc->update("update donors set tree_sort='999', tree_level=''");

        // get all root sites, but in case a name is missing (null), sort it to the bottom
        $q="select, ROOT.netsite_id, from netsite_root_ids ROOT
            left join netsites NS USING (netsite_id)
            order by ifnull(,'zzz') ASC";            // put nulls on bottom

        // setup sortcodes on each and recursively down the line
        $currentSortCode=1;     //the current sort code resets at each tree level
        foreach($res as $r){
            $this->setSortCode_recurs($r->id, $r->netsite_id, "", $currentSortCode++, $level);

    // The sortPrefix is the current sites parent... (ie. "AAA-BBB-" is the parent of "AAA-BBB-CCC")
    // currentSort is the current ID for this node
    private function setSortCode_recurs($id, $netsite_id, $sortPrefix, $currentSort, $level, $recurseLevel=1){
        if($recurseLevel++ > 999) return;    //loop safety

        // set current node
        $mySortCode = $sortPrefix . str_pad($currentSort, $this->SORTCODE_LEN, '0', STR_PAD_LEFT);

        // update myself with propert sort code
        $q="update donors SET tree_sort=?, tree_level=? where id=?";
        $this->dbc->update($q, [$mySortCode, $level, $id]);
        echo str_repeat("   ",$level-1) . "Level $level: $mySortCode    - set to $id\n";

        // get all child nodes, and update those
        $q="select, D.netsite_id, from donors D
             left join netsites NS USING (netsite_id)
             WHERE D.`donor_netsite_id` = ?
             order by ASC";
        $res=$this->dbc->select($q, [$netsite_id]);
            $nextPrefix = $mySortCode . "-";
            foreach($res as $r){
                $this->setSortCode_recurs($r->id, $r->netsite_id, $nextPrefix, $nextLevelSortCode++, $level, $recurseLevel);

There's probably a better way to do, would love to hear other ideas...


Very creative!

Next level would be to add expand/collapse. Maybe have custom columns button with + and - icons. Clicking retransforms the underlying data.

@bradlymathews - yes was thinking about that.
Since all the nodes are based on the "tree sort code"


then to collapse the "001" root tree, I suppose the transform query could .filter() out all nodes that start with "001-"

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