Access 2010: The Missing Manual

Data Corruption

Data corruption—the term strikes fear into the heart of the hardiest Access guru. Hopefully, the people who use your database will be well behaved, the network it sits on will remain reliable, and your database will never be in danger. But just in case life isn’t that kind to you, it’s important to be prepared.

Data corruption is a catch-all term that describes what happens when part of a database file is damaged. Imagine Jessica Baxter is in the middle of applying a large update when a power failure hits (or an office prankster pulls out her network cable). The back-end database will be left in an invalid state, because only part of Jessica’s information will have been successfully received. As a result, the record she was working with may be scrambled beyond recognition. And if you’re particularly unlucky, the problem can affect more than one record or even make the whole database act a little odd.

Figure 19-13. If you open a file in Exclusive mode, no one else can open it until you close it. If you open a file in Read-Only mode, you can’t make any changes.

Diagnosing (and Fixing) Corrupt Databases

Every Access expert should have basic data corruption survival skills. First, you need to be able to spot when a database has gone bad. Here are some telltale signs:

• Cryptic error messages that appear for no good reason, like “out of memory.” (Keep in mind ...