public function renderDropForeignKeys()
    {
        $foreignKeys = $this->getTableForeignKeys();

        if (!$foreignKeys) {
            return '';
        }

        $source = '';
        foreach ($foreignKeys as $foreignKey) {
            $name = $this->serializeIndexNameToAttribute($foreignKey->getName());
            $source .= "\n" . '$table->dropForeign(' . $name . ');';
        }

        return trim($source);
    }