To store the information of different products sold to the customers, we have to add an entity with the name: Product to our application. Also, we need to define a relationship between the Customer and the Product entity. As a customer can purchase several products, there will be a one to many relationship between the Customer and the Product entity. Let us double-click the prob.xcdatamodel file from the Resources group to open the Xcode's data modeling tool. We find a Customer's entity (as shown in the following screenshot) already there that we created in Chapter 4, Designing Data Model and Building Data Objects for Customers.
We can see that the Customer entity contains three attributes of the String data type: name, emailid, and contactno that will be used for storing the customer's information. To add the Product entity to our data model follow the given steps:
1. Select the + (plus) button at the bottom of the Entity pane or choose Design ...
