Prado\Data\ActiveRecord\Relations\TActiveRecordRelation::findForeignKeys PHP Метод

    protected function findForeignKeys($from, $matchesRecord, $loose = false)
    {
        $gateway = $matchesRecord->getRecordGateway();
        $recordTableInfo = $gateway->getRecordTableInfo($matchesRecord);
        $matchingTableName = strtolower($recordTableInfo->getTableName());
        $matchingFullTableName = strtolower($recordTableInfo->getTableFullName());
        $tableInfo = $from;
        if ($from instanceof TActiveRecord) {
            $tableInfo = $gateway->getRecordTableInfo($from);
        }
        //find first non-empty FK
        foreach ($tableInfo->getForeignKeys() as $fkeys) {
            $fkTable = strtolower($fkeys['table']);
            if ($fkTable === $matchingTableName || $fkTable === $matchingFullTableName) {
                $hasFkField = !$loose && $this->getContext()->hasFkField();
                $key = $hasFkField ? $this->getFkFields($fkeys['keys']) : $fkeys['keys'];
                if (!empty($key)) {
                    return $key;
                }
            }
        }
        //none found
        $matching = $gateway->getRecordTableInfo($matchesRecord)->getTableFullName();
        throw new TActiveRecordException('ar_relations_missing_fk', $tableInfo->getTableFullName(), $matching);
    }