Also known as Single Point of Truth, “don’t repeat yourself” or DRY is a process philosophy seeking to reduce duplication especially in computing. This philosophy stress on that information should not be duplicated because it makes the change more difficult, it can lessen clarity and may lead to inconsistency. DRY is from Andy Hunt’s and Dave Thomas’ principle in the book of Pragmatic Programmer. A revision of any single element of a system does not alter other logically-unrelated elements when the DRY principle is effectively applied. Moreover, elements are kept in sync because elements that are logically related all change predictably and evenly.