How to use Oracle flashback to query data?

2 years ago
Olivia Parker
2 minutes

To use Flashback Query in Oracle to retrieve data, you can follow these steps:

  1. Make sure you have sufficient privileges to perform flashback operations. This usually requires having FLASHBACK privileges or a DBA role.
  2. Retrieve data using flashback query statements. You can utilize the FLASHBACK TABLE statement to flashback data from one or more tables, or use the FLASHBACK QUERY statement for more complex queries. For instance, to flashback a table, you can use the following syntax:
  3. Roll back the table to a previous timestamp based on a specified time interval.
  4. Where is the name of the table to be flashed back, and is the time period to flash back to.
  5. A flashback query can be executed using the following syntax:
  6. Retrieve all the records from the specified table at a past timestamp based on a given time interval and conditions.
  7. is the name of the table to be queried, is the time period to be queried, which serves as the search condition.
  8. Execute a flashback query statement to retrieve the desired data.

It is important to note that flashback queries can only be used if flashback is enabled in the database. If flashback is not enabled, you can enable it at the database level using the following statement.

ALTER DATABASE FLASHBACK ON;

In addition, the availability of flashback queries depends on the settings and configurations of the database. If the time period you want to query exceeds the retention time of the flashback logs, the flashback query may not be successful.

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