Александр Медведев (Все сообщения пользователя)

            new Entity\StringField('USER_ID' , array(  // ссылка на поле другой таблицы
                'data_type' => 'Bitrix\Main\UserTable',
                'reference' => array('=this.USER_ID' => 'ref.NAME')
            )),

use Bitrix\Main\ORM\Fields\IntegerField;
use Bitrix\Main\ORM\Fields\Relations\Reference;
use Bitrix\Main\ORM\Query\Join;
use Bitrix\Main\UserTable;
...

new IntegerField( 'user_id' ),
new Reference( 'user', UserTable::class, Join::on( 'this.user_id', 'ref.ID' ) )

use Bitrix\Iblock\PropertyEnumerationTable;
use Bitrix\Iblock\PropertyTable;
use Bitrix\Iblock\PropertyValueTable;
use Bitrix\Main\ORM\Fields\Relations\Reference;
use Bitrix\Main\ORM\Query\Filter\ConditionTree;
use Bitrix\Main\ORM\Query\Query;

$item = PropertyValueTable::query()
    ->setSelect([
        'PROPERTY_VALUE' => 'PE.VALUE',
        'PROPERTY_CODE' => 'PB.CODE',
    ])
    ->where('IBLOCK_ELEMENT_ID', $elementId)
    ->where(
        Query::filter()
            ->logic(ConditionTree::LOGIC_OR)
            ->where('PB.CODE', 'OPERATIVNAYA_PAMYAT')
            ->where('PB.CODE', 'VSTROENNAYA_PAMYAT')
    )
    ->registerRuntimeField(
        new Reference(
            'PE',
            PropertyEnumerationTable::class,
            [
                '=this.IBLOCK_PROPERTY_ID' => 'ref.PROPERTY_ID',
                '=this.VALUE' => 'ref.ID',
            ]
        )
    )
    ->registerRuntimeField(
        new Reference(
            'PB',
            PropertyTable::class,
            [
                '=this.IBLOCK_PROPERTY_ID' => 'ref.ID',
            ]
        )
    )
    ->fetchObject();

$item = \Bitrix\Iblock\Elements\ElementProductTable::query()
    ->setSelect( [
        'OPERATIVNAYA_PAMYAT',
        'VSTROENNAYA_PAMYAT'
    ] )
    ->where( 'ID', $elementId)
    ->fetchObject();

$db = \Bitrix\Main\Application::getConnection();
$table = \Berest\Edu\LessonTable::getEntity()->getDBTableName();


if ($db->isTableExists($table)) {
    $db->dropTable($table);
}