Re: Thinking out loud - a continuation...

On 12-03-22 11:58 AM, Jay Blanchard wrote:

[snip]

Fix this code... I've come across codebases that did this specific type of nested querying and it resulted in 10000 queries to the database on every page. Instead, create a layered approach:

     1. Select your root elements.
     2. Loop over in PHP and create an array of child IDs.
     3. Select the children from the database.
     4. Go to step 2.

This way you will only every perform "depth" number of queries.

[/snip] I see what you're saying but I don't know that this reduces the number of queries - it just handles them in a different order. How do I get to the output that I need?

It definitely reduces the queries... your current method gets all the first level nodes in one query, then performs a query for every single parent node. Mine only performs a query for each level in the tree. If you have 5 nodes at the first level you will perform 6 queries. Mine will perform 2. To generate the nesting structure at each level you track the level members. Something like the following (untested pseudoish): <?php $parents = query_for_first_level(); $root = &$parents; while( $parents ) {

    $parentIds = array();
    foreach( $parents as $parent )
    {
        $parentIds[$parent['id']] = $parent['id'];
    }

    $children = query_for_children( $parentIds );
    foreach( $children as &$child )
    {
        $parents[$child['parentId']]['children'][] = &$child;
    }

    $parents = &$children;

} $jsonData = JSON_encode( $root ); ?> Cheers, Rob. -- E-Mail Disclaimer: Information contained in this message and any attached documents is considered confidential and legally protected. This message is intended solely for the addressee(s). Disclosure, copying, and distribution are prohibited unless authorized.