Knowledge Base

get_nodes()

Description

Get all nodes from database for a specific metadata field or parent.

Use $parent = NULL and recursive = TRUE to get all nodes for a category tree field

Use $offset and $rows only when returning a subset.

IMPORTANT: this is normally used with category trees, but can also be used with
other fixed field types which allow multiple values eg. dynamic keywords list and checkbox list.
This allows field type changes to be made between these three types without losing sight of all nodes.
IMPORTANT! For non-fixed list fields this is capped at 10000
to avoid out of memory errors

Parameters

Column	Type	Default	Description
$resource_type_field	integer		ID of the metadata field
$parent	integer	null	ID of parent node
$recursive	boolean	false	Set to true to get children nodes as well.
$offset	integer	null	Specifies the offset of the first row to return
$rows	integer	null	Specifies the maximum number of rows to return.
$name	string	''	Filter by name of node
$use_count	boolean	false	Show how many resources use a particular node in the node properties
$order_by_translated_name	boolean	false	Flag to order by translated names rather then the order_by column

Return

array

Location

include/node_functions.php lines 291 to 403

Definition

 
function get_nodes($resource_type_field, $parent = null, $recursive = false, $offset = null, $rows = null, $name = '', 
    $use_count = false, $order_by_translated_name = false)
    {
    global $FIXED_LIST_FIELD_TYPES;
    debug_function_call("get_nodes", func_get_args());

    if(!is_int_loose( $resource_type_field))
        {
        return [];    
        }
        
    if(!is_null($parent))
        {
        if ($parent == ""){$parent=null;}
        else {$parent = (int) $parent;}
        }

    $fieldinfo  = get_resource_type_field($resource_type_field);
    if($fieldinfo === false){return false;}
    if(!in_array($fieldinfo["type"],$FIXED_LIST_FIELD_TYPES) && (is_null($rows) || (int)$rows > 10000 ))
        {
        $rows = 10000;
        }

    $return_nodes = array();

    $parameters= [];
    $sql = "";
    add_sql_node_language($sql,$parameters);

    $parameters[] = "i";$parameters[] = $resource_type_field;

    // Filter by name if required
    $filter_by_name = '';
    if('' != $name)
        {
        $filter_by_name = " AND `name` LIKE ?";
        $parameters[]="s";$parameters[]="%" . $name . "%";
        }

    // Option to include a usage count alongside each node
    $use_count_sql="";
    if($use_count)
        {
        $use_count_sql = ",(SELECT count(resource) FROM resource_node WHERE resource_node.resource > 0 AND resource_node.node = node.ref) AS use_count";
        }  

    $parent_sql = is_null($parent) ? ($recursive ? "TRUE" : "parent IS NULL") : ("parent = ?");
    if (strpos($parent_sql,"?")!==false) {$parameters[]="i";$parameters[]=$parent;}
    
    // Order by translated_name or order_by based on flag
    $order_by = $order_by_translated_name ? "translated_name" : "order_by";

    // Check if limiting is required
    $limit = '';
    if(!is_null($offset) && is_int($offset)) # Offset specified
        {
        if(!is_null($rows) && is_int($rows)) # Row limit specified
            {
            $limit = "LIMIT ?,?";
            $parameters[]="i";$parameters[]=$offset;
            $parameters[]="i";$parameters[]=$rows;
            }
        else # Row limit absent
            {
            $limit = "LIMIT ?,999999999"; # Use a large arbitrary limit
            $parameters[]="i";$parameters[]=$offset;
            }
        }
    else # Offset not specified
        {
        if(!is_null($rows) && is_int($rows)) # Row limit specified
            {
            $limit = "LIMIT ?";
            $parameters[]="i";$parameters[]=$rows;
            }
        }
        
    $query = "SELECT " . columns_in("node") . $sql . $use_count_sql . "
        FROM node 
        WHERE resource_type_field = ?
        " . $filter_by_name . "
        AND " . $parent_sql . "
        ORDER BY " . $order_by . ", ref ASC
        " . $limit;

    $sqlcache = in_array($fieldinfo["type"],$FIXED_LIST_FIELD_TYPES) ? "schema" : "";
    $nodes = ps_query($query,$parameters,$sqlcache);
  
    // No need to recurse if no parent was specified as we already have all nodes
    if($recursive && (int)$parent > 0)
        {
        foreach($nodes as $node)
            {
            foreach(get_nodes($resource_type_field, $node['ref'], true) as $sub_node)
                {
                array_push($nodes, $sub_node);
                }
            }
        }
    else
        {
        $return_nodes = $nodes;
        }

    if($recursive)
        {
        // Need to reorder so that parents are ordered by first, with children between (query will have returned them all according to the passed order_by)
        $return_nodes = order_tree_nodes($return_nodes);
        }
   
    return $return_nodes;
    }


This article was last updated 18th May 2024 21:35 Europe/London time based on the source file dated 14th May 2024 18:25 Europe/London time.