section.php

См. документацию.

<?php
namespace Bitrix\Iblock\Model;
 
use Bitrix\Iblock\Iblock;
use Bitrix\Iblock\IblockTable;
use Bitrix\Iblock\SectionTable;
 
class Section
{
    private static $entityInstance = [];

    final public static function compileEntityByIblock($iblock)
    {
        $iblockId = static::resolveIblockId($iblock);
 
        if ($iblockId <= 0)
        {
            return null;
        }
 
        if (!isset(self::$entityInstance[$iblockId]))
        {
            $className = 'Section'.$iblockId.'Table';
            $entityName = "\\Bitrix\\Iblock\\".$className;
            $referenceName = 'Bitrix\Iblock\Section'.$iblockId;
            $entity = '
            namespace Bitrix\Iblock;
            class '.$className.' extends \Bitrix\Iblock\SectionTable
            {
                public static function getUfId()
                {
                    return "IBLOCK_'.$iblockId.'_SECTION";
                }
                
                public static function getMap(): array
                {
                    $fields = parent::getMap();
                    $fields["PARENT_SECTION"] = array(
                        "data_type" => "'.$referenceName.'",
                        "reference" => array("=this.IBLOCK_SECTION_ID" => "ref.ID"),
                    );
                    return $fields;
                }
                
                public static function setDefaultScope($query)
                {
                    return $query->where("IBLOCK_ID", '.$iblockId.');
                }
            }';
            eval($entity);
            self::$entityInstance[$iblockId] = $entityName;
        }
 
        return self::$entityInstance[$iblockId];
    }

    protected static function resolveIblockId($iblock): ?int
    {
        $iblockId = null;
 
        if ($iblock instanceof Iblock)
        {
            $iblockId = $iblock->getId();
        }
        elseif (is_string($iblock))
        {
            $row = IblockTable::query()
                ->addSelect('ID')
                ->where('API_CODE', $iblock)
                ->fetch();
 
            if (!empty($row))
            {
                $iblockId = (int)$row['ID'];
            }
        }
 
        if (empty($iblockId) && is_numeric($iblock))
        {
            $iblockId = (int)$iblock;
        }
 
        return $iblockId;
    }
}