Summary

This chapter dealt with Flashback technology. While it wasn't intended to cover temporality and monitor object states over time, it offered techniques to get the state at a defined point in the past. The Flashback operation can be done for the whole database or even a particular table, or the historical data image can be obtained by the query itself. The Select statement provides the most powerful solution from a temporal management point of view because the stored data is not changed – just the transaction logs are applied to construct the result set. As stated, the Flashback execution is based on Online and Archive transaction logs, by which the historical state is reconstructed. The availability of the logs is crucial for the activity and reliability of the solution. Regarding performance, Flashback commonly provides a more powerful solution compared to restore and recovery. On the other hand, a precise temporal model can ensure significant performance benefits...