How can you efficiently recover all your data when your desktop, laptop or tablet crashes or loses some of the data? Furthermore, databases, which are collections of interrelated data, are used rampantly by all organizations involved such as, hospitals, banks, travel agencies, hotels, shopping complexes and you name it! So what do you do when these databases with huge collections of important data suddenly get sabotaged? This article touches on these aspects, and gives you tips on data recoveries. So why don’t you read on?
First of all, let’s talk about your laptop, desktop or tablet that you use on a daily basis. The best ways to recover all the data on these machines when they crash without warning or say, lose part of the data due to some error happening is to keep a backup of all your data in flash drives which have a good many GB’s of storage in varieties. Find out and then decide how many GB’s of data from your machine and/or together with storage from other sources you need and then purchase that flash drive within that capacity or more and keep a backup of all your important data. You need to update your backup weekly preferably, if not daily. This will enable you to recover all your data on your computer by using the backups.
Let’s say you have a huge collection of audio, photos, files in different formats and they are continually growing on your computer and you want to backup all of your data from Day 1 until today and also, you are not being able to keep all your data intact on your computer. In fact, you are dealing with terabytes (TB) of data and that means you need to backup all your data all along and also remove some of the old data from your computer to make some space for new ones. The best way to maintain data in this case is to use an external portable hard drive and backup everything in it. This kind of external hard drive can store several TB’s of data and you get to choose which size is right for you.
If you do not deal with GB’s and TB’s of data but still need to backup your computer’s data you can use rewritable CD-ROM disks which will be able to store a good many megabytes (MB’s) of data. I guess you get the idea.
Now let us consider recovery approaches for databases used by organizations as I mentioned earlier.
Periodically, the entire database is copied (backed up), typically to tapes, compact disks, or external portable hard drives (which I described earlier). Backups also can be made incrementally i.e. only the changes since the last backup are stored. A log file is used to record the changes in the database at each update, typically the old and new values of the updated attribute(s).
When an error occurs:
- If the database itself is damaged (media failure, e.g. by a head crash)
– The last backup is loaded
– The updates of all committed (completed) transactions that were executed since the time of last backup are shown by the log. Those transactions that had not committed yet need to be restarted.
- If the database itself is not damaged, but the correctness of the contents cannot be guaranteed (e.g. because a program with updates crashed)
– The log is used for repeating committed changes (redo) and reversing non-committed changes (undo). Then, the non-committed transactions can be restarted.
Summing up, it always boils down to the fact that whether you are concerned with your computer’s data or a database’s data, you will need backups, plain and simple.
Rosina S Khan wrote this article in order to provide information on recovery approaches for data on your PC’s and laptops and/or any organization’s important data in large databases.