Author Question: Explain the purpose of transaction logs and checkpoints. What will be an ideal ... (Read 60 times)

washai · **on:** Jul 7, 2018

Explain the purpose of transaction logs and checkpoints.

What will be an ideal response?

Question 2

Semantic objects represent the user's perceptions more closely than the E-R model.

Indicate whether the statement is true or false

AngeliqueG · **Reply #1 on:** Jul 7, 2018

Answer to Question 1

Transaction logs are created to facilitate the recovery of the database. All transactions that make changes to the database are recorded in the transaction log before they are applied to the database. In the event that the database fails the transactions in the log can be used to undo changes made by transactions that were not committed, and to redo changes that were committed since the database was last saved. Checkpoints are used in conjunction with transaction logs. A checkpoint is a marker for when the last time the database and the transaction log were synchronized. If the database must be restored, only after images for transactions that began after the last checkpoint have to be applied.

Answer to Question 2

TRUE