DRY really isn't about compressing the data on which your code operates. It's about reducing the number of times your code coordinates the same knowledge about

DRY really isn't about compressing the data on which your code operates. It's about reducing the number of times your code coordinates the same knowledge about those operations across its text. If you add a field to a record and have to edit the code more than a couple of places to deal with that, you're repeating yourself. If you repeat yourself, those different parts of the code are not only more work to understand and to change, but are more likely to diverge from one another as they are edited in slightly different directions.