First, do not work after startup or Oracle database fails to start
Once the database appears the situation can not be started, you first need to check whether the system table undamaged state, usually the case, if the system is not damaged so easily table for data recovery, if the system tables have been damaged, you need data recovery personnel manual analysis of the structure of the table to check, so data recovery period is relatively long, but the data recovery success rate is still high, do not worry about data recovery failed.
Two, ASM to store the Oracle database is damaged
This failure is usually caused by equipment failure part ASM, or database data due to the other causes a reset ASM loss. After this happens need to determine whether the amount of data written after the failure, if the situation does not continue to write large amounts of data to the database is usually can recover data. Therefore, attention should also point is that, as much as possible to avoid the need to write data in the device once the oracle database of such failure occurs, so as not to destroy the original data.
Third, the database accidentally deleted, formatted or other data files are missing
Since the Oracle database format error, accidentally deleted due to improper operation and other data in the database after the loss, remember not to misuse the database after the operation of writing data. If the data is not written in the case of data loss, regardless of any operating system we can complete restore of the database by organizational rules database, the only drawback is the need to restore manually check the data file name.
Four, Oracle data files and dump partially damaged file corruption
If the oracle data file is partially damaged, you want to restore data you need professional data recovery and restructuring practitioners to extract data before they can be restored, and data recovery for a long time.
Oracle dump file damage at the damaged portion is removed, the rest can be added to normal data table.
Database Data Recovery recommendation
If it is because the software causes data loss, you should do after data loss in the first time the maximum possible to avoid doing too much storage operations and timely data mirroring. If data is lost due to hardware failures you will need to avoid hardware powered devices attempt to avoid further damage to the device to increase the difficulty of data recovery.