SQL Server Database Corruption & Backup Myths

Overview

There are various myths regarding the corruption in SQL server. Let us understand what are the various myths & misconceptions of SQL server database corruption and how to fix this problem.

But first, let us understand how many types of corruption are there in SQL Server Database. There are two types of corruption:

• Physical Corruption
• Logical Corruption

Physical Corruption:

There are various reasons why physical corruption occurs. Some of them are listed below:

• Issues with the I/O subsystem: These issues are related to operating system, third-party file system filter drivers, RAID controllers, device drivers, network hardware, etc.
• Problems associated with the host system hardware: Most probably, this is an error associated with the memory
• SQL server bugs: These bugs are related to corruption
• Using a hex editor
• Physical corruption is usually reported by DBCC CHECKDB and a large number of cases are caused by any sort of physical failure .

Logical Corruption:

The most probable reasons due to which logical corruption occurs are listed below:

• Application bug: Here, following case arises:
  1. The program deletes a single part of a hereditary data relationship but keeps the other one.
  2. The application designer did not implement a proper constraint.
  3. The application designer does not deal with transaction rollback properly.
• Accidental delete/ upgrade: Somebody updates or deletes the data incorrectly
• SQL server Bug

Inshort, physical failure causes physical corruption. In a similar manner, application error causes logical corruption.

SQL Server Corruption Myths

The various misconceptions are mentioned below:

• A program can cause physical corruption
• Halting a shrink operation can result in corruption
• Halting an index rebuild can result in any kind of corruption
• Executing DBCC CHECKDB command without repair can cause corruption
• Generating a database snapshot can result in any kind of corruption

Tip: You can try various manual approach to fix SQL Server corruption issue. But if you are looking for quick & reliable solution, you can recover it by SQL Database Repair Tool.

SQL Server backup myths

There are numerous misconceptions when it comes to restoring operation in SQL server. Some of them as listed as follows:

• It is possible to perform a point-in-time restore operation with the use of WITH STOPAT on a differential or full backup.
• It is possible to continue with the backup process sequence after using WITH CONTINUE_AFTER_ERROR
• It is possible to restore various parts of a database to different point-in-time.
• Filegroups from different databases can be backed up together in a new database
• On creation of backup, index fragmentation (or update statistics, etc.) can be removed
• A database can be shrunk while obtaining a backup
• The database can be backed up to any lower edition of SQL server
• A database can be restored anytime to any version of the SQL server
• Restore sequence will break upon using the command WITH STANDBY
• To recover from the corruption, restoring data is the best method
• During a backup process, instant file initialization will not work if the data was not restored on the SQL server with the activation of instant file initialization
• A point-in-time backup can also be done in a time covered by a log of backup
• The overall SQL database pages can be backed up on a single page.
• The entire backup will be authenticated by RESTORE WITH VERIFYONLY command
• The restored copy of backup of an encoded (encrypted) database can be obtained without first restoring the server certificate
• Only an enterprise edition of SQL server 2008 can produce a compressed backup
• The backup of a database can be created from a lower version to skip the upgrade procedure
• If a backup is taken on a 64-bit instance, it cannot be restored in a 32-bit instance, and vice-versa
• Before creating a backup, a user should compulsorily drop a database.

Tip:If you are looking for reliable solution to restore .bak file, you can use SQL Backup Repair Utility.

Wrapping Up

The write-up deals with the various SQL Server database corruption myths. However, there are third-party utilities to facilitate easy working on the SQL server. To deal with the SQL server corruption,you can try manual approach but if you dont want your data to be lost, it is better to use an automated tool like SQL Recovery. Also, to fix corrupted SQL .bak file , it is recommended to use SQL Recovery Backup Tool.