It seems like there's not a site out there anymore that doesn't use a database of some sort. Frankly, they're just a simple way to get the storage you need without the hassle of having to manage the resource yourself. It even comes with its own language to help query the data! Of course, with the good comes the bad, and this new article from IBM's developerWorks site about five common database mistakes.

If only there were one way to use databases correctly... You can create database design, database access, and the PHP business logic code that sits on top of it in any number of ways, and you often end up getting it wrong. This article illustrates five common problems in database design, in the PHP code that accesses databases, and how to fix these problems when you see them.

The problems they discuss are:

• Using MySQL directly
• Not using auto-increment functionality
• Using multiple databases
• Not using relations
• The n+1 pattern

Each of the items is discussed and explained with code samples for both the good and the bad side to make comparison easier. Knowing these issues before you develop your system definitely makes it easier, but they're still useful as a tool to fix things as well.