Demo: Entities

- [Instructor] So now that we've got the flow under control, … we have to start thinking about not what is happening, … but how it's happening. … Who's doing it, in other words? … So the next step in this process is … to start adding aggregates or entities … or some kind of label of who is receiving the event … and then doing work with the event. … So the entities are all labeled with yellow stickies, … so let's go to yellow here. … The cart has been purchased, … and we need to issue an invoice. … Who's going to do that? … So I'm going to just grab out of the hat a sales clerk, … somebody whose job it is to issue invoices to customers. … If you were working in a store, … this is the equivalent of a cash register receipt. … And the sales clerk is going to span these two events. … By the same token, if we're requesting payment, … we need a different kind of entity to do that. … This kind of entity is going to be a cashier. … In other words, I'm separating concerns here. … I'm separating the interacting with the customer concern …