How do you do flashbacks on a table?
How do you do flashbacks on a table?
Create a test table, enable row movement and check the SCN of the database. Create a new row in the test table, commit the change and check the SCN again. Flashback the table to the point in time represented by the first SCN, before the row was created, and check the contents of the table.
How do you flashback a table in SQL?
To flash back a table to an earlier SCN or timestamp, you must have either the FLASHBACK object privilege on the table or the FLASHBACK ANY TABLE system privilege. In addition, you must have the SELECT , INSERT , DELETE , and ALTER object privileges on the table.
What is a flashback table statement?
Purpose. Use the FLASHBACK TABLE statement to restore an earlier state of a table in the event of human or application error. The time in the past to which the table can be flashed back is dependent on the amount of undo data in the system.
How do I create a flashback in Oracle?
How to Enable Oracle 12c Flashback Database
- Shut down the database and start up the database in mount mode in SQL*Plus:
- Confirm that the database is in ARCHIVELOG mode, which is required for Flashback Database, and enable ARCHIVELOG mode if needed.
- Set the flashback retention target to the desired value (in minutes).
How do I purge a table in Oracle?
When issuing a DROP TABLE statement in Oracle, you can specify the PURGE option. The PURGE option will purge the table and its dependent objects so that they do not appear in the recycle bin. The risk of specifying the PURGE option is that you will not be able to recover the table.
How does Oracle Flashback database work?
Use the FLASHBACK DATABASE command to rewind the database to a target time, SCN, or log sequence number. This command works by undoing changes made by Oracle Database to the data files that exist when you run the command. Flashback can fix logical failures, but not physical failures.
What is purge table?
Purpose. Use the PURGE statement to remove a table or index from your recycle bin and release all of the space associated with the object, or to remove the entire recycle bin, or to remove part of all of a dropped tablespace from the recycle bin.
How do you know if a database is flashback?
Use the following command to check if Flashback Database is enabled for your target database: SELECT FLASHBACK_ON FROM V$DATABASE; To enable Flashback Database: Ensure that you configure a fast recovery area and that the database is running in ARCHIVELOG mode.
What is a flashback table?
Restores all data in a specified table to a previous point in the time described by a timestamp or SCN.
What are external tables in Oracle?
The Oracle external tables feature allows us to access data in external sources as if it is a table in the database. External tables are read-only. No data manipulation language (DML) operations is allowed on an external table. An external table does not describe any data that is stored in the database.
How to flashback a pluggable database?
Flashback a Pluggable Database: create a restore point. connect inside the PDB and make changes. Flashback the PDB to the restore point. Check the table content is missing.
What is Oracle Flashback Query?
To use Oracle Flashback Query, use a SELECT statement with an AS OF clause. Oracle Flashback Query retrieves data as it existed at an earlier time. The query explicitly references a past time through a time stamp or System Change Number (SCN). It returns committed data that was current at that point in time.