Causes and workarounds for SQL database corruption

Many staff members are still using SQL SEVER for a variety of reasons, and the SQL database can be damaged to varying degrees, which greatly affects employees ' normal work. The loss of data can also cause huge losses to the company. This article provides additional information about the causes and workarounds of SQL database corruption.

Report "823" error when attaching database file MDF and log file LDF. Cause of failure:

(1) A sudden crash or power outage during database reading and writing.

(2) The server restarts and the database has a "suspect" status after the restart.

(3) disk I/O error

in the above possible three kinds of sudden failure, due to the loss of buffered data, the database can not write the correct data, resulting in data structure disorder, after restarting the database can not be properly attached. "Internal consistency error" occurs when

makes a database restore from a previously backed-up database. This is often the database manager's biggest nightmare, obviously did a backup, but in the restoration found that the backup file is corrupted. This means that the database is missing and the consequences are very serious. The cause of the failure:

(1) The backup file and database are placed on the same physical hard disk, the hard drive fails, and the backup is corrupted.

(2) The backup media is corrupted, or the network backup is done, and the data is corrupted in the network transmission.

(3) The contents of the database are corrupted when they do a full backup, a file backup, or a filegroup backup. This is because SQL Server is doing data backup in order to save time, basically just very simple to copy the data page, do not do consistency check. However, when recovering, you need to restore the database (Recover) to a point in time when the transaction is consistent. If the corruption in the backup prevents SQL Server from rolling back (redo and undo), the recovery action encounters an error.

(4) This error can also occur when backing up the database because there is a bad path in the disk and the backed-up MDF file is incomplete.

When the database above failure, you need to repair the database files in the bad page, if the structure of the MDF file is not very clear, please do not modify the original file, this will be counterproductive, resulting in greater loss. We can first back up the database files, and then the backup file with the command to repair, often this situation after the command repair, the data will be lost part!

A better solution is to download the Invincible data recovery software, install the run on the computer, scan the SQL database to find the missing file click Restore. Recovering data is an easy task as long as the data is lost without any reading or writing to the SQL database. Data Recovery Software free version: Http://dl.pconline.com.cn/download/90972.html

Causes and workarounds for SQL database corruption