Data Model

Core Data describes the data in terms of a data model. A data model is used to define the structure of the data in terms of entities, properties, and their relationships.

Entities

Because Core Data maintains data in terms of objects, an entity is an individual data object to represent complete information of the person, item, object, and so on. For example, customer is an entity, which represents information of customers, such as name, address, e-mail ID, contact number, products purchased, date of purchase, and so on. Similarly, the product is an entity, which represents the information of a product, such as name of the product, price, weight, and so on. An entity consists of properties that are a combination of attributes and relationships. An entity in Xcode's Data Model Editor may appear as shown in the following screenshot:

Properties

Properties of an entity give detailed information about it, such as what are its attributes and how it is related to other entities. A property...