Question

What does it mean when it is specified that certain transaction operations must be redone to ensure that all the operations of a committed transaction have been applied successfully to the database?

1) It means that the transaction operations need to be rolled back and re-executed.
2) It means that the transaction operations need to be committed again to the database.
3) It means that the transaction operations need to be undone and removed from the database.
4) It means that the transaction operations need to be ignored and not applied to the database.

Answer 1

To redo transaction operations means to reapply actions from a log to a database to ensure all changes of a committed transaction persist after a crash or failure. This is part of the database recovery process known as redo logging.

Step-by-step explanation:

When it is specified that certain transaction operations must be redone to ensure that all the operations of a committed transaction have been applied successfully to the database, it generally refers to a process known as redo logging in the context of database recovery mechanisms. This does not mean that the operations need to be rolled back or re-executed from the beginning, nor does it imply that they need to be committed again or undone and removed from the database. The correct answer is 1) It means that the transaction operations need to be redone, which in the context of databases often means reapplying actions from a log to ensure the database reflects all the changes of the committed transaction after a crash or failure.