Corruption manifests itself in an Oracle database in two ways. An Oracle data block may contain invalid header or content of the blockade could be logically inconsistent. In both previous cases, that could the terrible loss of information, including data from applications and user data from the control of Oracle, etc. Oracle offers a complete list of solutions for the treatment of these cases. May have different parameters (‘DB_BLOCK_CHECKING’, DB_BLOCK_CHECKSUM’, etc.) on the basis of data to detect corruption. The Oracle Recovery Manager (RMAN), you can implement a database backup and recovery plan. However, if these methods do not work, you can use third-party software Oracle Database Recovery to recover the lost or damaged.

For example, when you start Oracle, you may receive the following error message:
“ORA-01092. Oracle Example finished with forced offline”
If you look at the warning log at this stage, there is some error:
“ORA-01578: ORACLE data block corrupted (file # 1, # 57 371 block)”
O
“ORA-01110: data file 1: ‘G: \ oracle \ \ product 10.1.0 \ oradata \ HRDEV \ SYSTEM01.DBF”
The error shows the occurrence of a block can corrupt Oracle database, which has led to an unexpected shutdown the Oracle instance. This is usually caused by several factors, such as incorrect permissions, the lack of data files or operating system problems, etc.

To confirm block corruption, you should ‘db_verify’ outer line of command in suspicion. If the result shows the errors in the positions of the same page, it is possible to solve corruption groped one of the methods listed:
• You can try deleting and re-damaged product, if they are worried about data loss. You can recover all lost data from external sources. To identify objects that are corrupt, run the following query:
‘Selection segment_type tablespace_name, owner,
segment_name
of DBA_EXTENTS
where file_id <= id damaged file <
and <Block block_id and #> block_id between the blocks-1 + ”
This query assigns the physical location of the damaged property.
• Restore data from backup is a reliable way to save them all the best in all blocks in the file to be recovered.
• You must ‘dbms_repair leave “as a last resort for dealing with block corruption. It can help to recognize and repair damage to the Oracle database.

If you see the same mistakes in the database, you must use the help of a professional recovery software for the Oracle database. These tools effectively repair corrupt DBF files, damaged or inaccessible to all database objects to be restored, such as tables, views, procedures, triggers, functions, etc. who are looking for Oracle databases running on your system and allows you to selective extraction of components of the database.