You model your business using Entities (the ID matters) and Value Objects (the values matter). You use Repositories to retrieve and store them. You create them with the help of Factories. If an object is too complex for a single class, you’ll create Aggregates that will bind Entities & Value Objects under the same root. If a business logic doesn’t belong to a given object, you’ll define Services that will manipulate the involved elements. Eventually, when the state of the business changes (a change that matters to business experts), you’ll publish Domain Events to communicate the change.
Before you explore the data, write down a short list of what you expect to see in the data: the distribution of key variables, the relationships between important pairs of them, and so on. Such a list is essentially a prediction based on your current understanding of the business.
…s, the combination of the small touch target and the X screen being even longer makes this a chore. I feel badly for Donald Trump here. If/when he gets an iPhone X, there’s no way he’s going to be even halfway to being able to reach the control center area with those tiny hands of his. Sad!