Like any other file, the MDF file (MS SQL database file) can also get corrupted at any time. Few symptoms to help you identify that the database file is corrupted are when you cannot see all records stored in database components, the database file does not open, or the database is activated in a suspicious state. In most cases of MDF file corruption, the database administrator will get an error message which he / she tries to resolve by running the DBCC CHECKDB command or by restoring the file from an updated backup. DBCC CHECKDB command will help repair the MDF file in case of logical corruption, and if the command fails, the administrator will restore the data from an updated backup. However, the main problem only occurs when no database backup is available. For such cases, the database administrator has only one option – a third-party MDF recovery software.
To practically explain the above discussion, here is an error message that appears after corruption of MDF file:
Error 5101: Device Activation Error. The physical file name ‘C: % path to db% db_log.LDF’ may be incorrect. Then I get db Attach failed. “
The above error message appears when the administrator tries to open the MDF file and access the database objects. To resolve the above error message and repair the database file, when the database administrator runs DBCC CHECKDB (‘dbname’, REPAIR_REBUILD), he / she will encounter another error message as shown below:
Server: Msg 945, Level 14, State 2, Line 1
Database ‘dbname’ cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server error log for details. “
The above error appears because DBCC CHECKDB cannot fix the corruption. In such circumstances, if the backup of the above file is unavailable or corrupt, the administrator has no alternative but must use a commercial MDF recovery application.
An MDF recovery software provides complete recovery of all inaccessible database components from damaged MDF file. Such MDF recovery tools provide a full preview of all recoverable MS SQL database components before recovery. Most of these database recovery applications come with a demo version that provides a full understanding of the software.
MS SQL 2000, MS SQL 2005 and MS SQL 2008