PHP & MySQL® Web Development All-in-One Desk Reference for Dummies®

2.6. Restoring Your Data

At some point, one of your database tables might become damaged and unusable. It's unusual, but it happens. For instance, a hardware problem or an unexpected computer shutdown can cause corrupted tables. Sometimes, an anomaly in the data that confuses MySQL can cause corrupt tables. In some cases, a corrupt table can cause your MySQL server to shut down.

Here's a typical error message that signals a corrupted table:

Incorrect key file for table: 'tablename'.

You can replace the corrupted table(s) with the data stored in a backup copy.

However, in some cases, the database might be lost completely. For instance, if the computer on which your database resides breaks down and can't be fixed, your current database is lost — but your data isn't gone forever. You can replace the broken computer with a new computer and restore your database from a backup copy.

You can replace your current database table(s) with the database you've stored in a backup copy. The backup copy contains a snapshot of the data as it was when the copy was made. Of course, you don't get any of the changes to the database since the backup copy was made; you have to re-create those changes manually.

Again, if you access MySQL through an IT department or through a Web hosting company, you need to ask the MySQL administrator to restore your database from a backup. If you're the MySQL administrator, you can restore it yourself.

As we describe in Chapter 1 of this minibook, you build a database ...