Explain the concept of Transactional Box and its role in data processing.

Transactional Box is a concept that describes an area or container in which a set of operations is performed as a single transaction. In the context of data processing, this means that all operations within this area either complete successfully together or, in case of an error, all changes are rolled back, ensuring data integrity.

For example, in Go, you can represent a Transactional Box as a function that takes another function with operations and manages the beginning, commit, and rollback of the transaction:

func TransactionalBox(db *sql.DB, fn func(tx *sql.Tx) error) error {
    tx, err := db.Begin()
    if err != nil {
        return err
    }
    if err := fn(tx); err != nil {
        tx.Rollback()
        return err
    }
    return tx.Commit()
}

Thus, all operations inside fn are executed within a single transaction.