Overall, MySQL's popularity has attracted many web developers, some of them having no prior IT experience. When faced with the task of transforming a static website into a dynamic/transactional one, or integrating corporate data into the site, developers are sometimes inclined to improvise a data structure. This structure (or lack of structure) may work for a certain time but later fails because of lack of depth. Maybe the system initially works because it started small, with only a few functions planned and implemented, but falls apart when users ask more of it. A poorly designed data structure can only be patched to a certain extent. It can also have scaling issues, when the initial testing has been done with only a few rows of data.

The apparent facility of using the tools may hide the fact that database design depends upon essential principles. Eluding them can render an application costly to maintain, because correcting data structural errors after application coding has begun is time consuming.

Here is an example of the impact of MySQL in the ranks of non-IT people. I once saw this question in a phpMyAdmin discussion forum—I am citing it from memory: "I've installed MySQL and phpMyAdmin, now I need directions: what do I do next?" I answered "Maybe you could create a table, and then insert some data into it. Next you could browse for your data."

Clearly, those tools were perceived as interesting by this person, but I can only wonder what kind of table structure came into existence after this forum conversation.

We can think of data design as a sequence of steps whose goal is to produce the physical MySQL databases, tables, and columns necessary to support an application.

Starting with the outer shell, we first need to learn about our data by collecting it. We then start to organize these data elements by naming them appropriately. This is followed by regrouping the data elements into tables, taking into account the needed keys. Whereas the previous steps could have been done only on paper, the final step is to implement the model within MySQL's structure.

All these steps are covered in distinct chapters of this book.