Prices go up. People move. Companies merge. Overpasses need to be built. Life changes and the data in a database must be updated to reflect this. Additionally, sometimes design choices for tables and databases might need to be rethought, requiring changes to both the data and the structures in which the data is stored.
The phrases in this chapter focus on the hows and whys of changing data that is already stored within MySQL tables, with a little bit of changing MySQL tables thrown in for good measure.