![]() Simplifying application design by removing the need to store some kinds of temporal data. (For more information, see Temporal Validity Support.) Selecting data that was valid at a particular time or at any time within a user-defined valid time period.įor example, you can find employees with valid employee information as of a particular timestamp or between a specified start and end time in the specified valid time period. You can compare individual rows of table data or find intersections or unions of sets of rows.Ĭhecking the state of transactional data at a particular time.įor example, you can verify the account balance of a certain day. ![]() Recovering lost data or undoing incorrect, committed changes.įor example, if you mistakenly delete or update rows, and then commit them, you can immediately undo the mistake.Ĭomparing current data with the corresponding data at an earlier time.įor example, you can run a daily report that shows the change in data from yesterday. Recover terminated transactions by using database or process recovery Besides using it in flashback features, Oracle Database uses undo data to perform these actions: By using flashback features, you can use undo data to query past data or recover from logical damage. It is retained for the time specified by undo_retention, or up to the tuned undo retention in the presence of Automatic Undo Management (AUM). Undo data is persistent and survives a database shutdown. For example, if a user runs an UPDATE statement to change a salary from 1000 to 1100, then Oracle Database stores the value 1000 in the undo data. ![]() They rely on undo data, which are records of the effects of individual transactions. Oracle Flashback features use the Automatic Undo Management (AUM) system to obtain metadata and historical data for transactions. Roll back a transaction and its dependent transactions while the database remains online Recover tables or rows to a previous point in timeĪutomatically track and archive transactional data changes Perform queries that return metadata that shows a detailed history of changes to the database Oracle Flashback Technology is a group of Oracle Database features that let you view past states of database objects or to return database objects to a previous state without using point-in-time media recovery.
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