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Avoiding and Restoring a Corrupted Database
The information provided is for help with Commtest Instruments products:
QUESTION
I think my database has become corrupted. What can I do?
CAUSES:
If your database has become corrupted you may receive various error messages informing you of a problem. Alternatively you might find that some of your data is incorrect, incomplete or even lost entirely.
Some of the main causes of database corruption are:
- A power failure or power interruption on the computer that holds your database.
- Various defects in the database computer such as hard disk corruption, memory and cache faults etc.
- Defects caused by faulty network connections (in a multi-user environment).
- Exceeding the database size restriction. This is approximately 2 GB for a database running on a Linux platform and 4 GB for Windows (although 2 GB is the recommended size allowance).
- Running out of hard disk space when working with your database.
SOLUTION
If you have been making regular backup copies you can restore your database by overwriting the corrupt database with a clean copy.
- From the main menu select File>Database>Backup Options.
- Click the 'Files' tab.
- Choose a file to restore your database from then click Restore.
- A warning prompt window will appear informing you that any data that is not in this backup file will be erased. This is because the backup overwrites your active database, so any recordings that have been taken since the last backup will not be in this file and will therefore be lost. Click Yes to continue.
- The restore process will now proceed; some windows and progress bars will appear. Click OK when these have disappeared.
What if I don't have a Backup Copy?
If you have no backup copies you may still be able to salvage your database. The ib-aid webpage contains information on restoring corrupt databases. At the bottom of that page you will find another webpage address for various InterBase tools that may be able to restore your database.
How to Minimize your Risk of Database Corruption
- At a minimum you need to have an un-interruptible power supply (UPS) on the database PC to protect your PC from power surges and outages. A UPS can be purchased from any electronics store.
- Backup your database regularly so that you always have a clean copy to restore from. The more frequently you perform backups the less data you will lose e.g. if you perform nightly backups you will only lose the current day's newly collected data and/or any other changes you have made to your database. Consult your Ascent Software Reference Guide for full instructions on how to perform backups.
Note: If you are collecting data with a vbOnline instrument rather than a vb portable you can configure the Online Manager to schedule automatic backups as part of the Data Thinning process. Backups can be scheduled during the evening or any time that causes the least inconvenience. See the vbOnline Reference Guide for more information.
FAQ ID: 14771 Last Reviewed: 27/09/2005