The Core iOS Developer’s Cookbook, Fifth Edition

Attributes and Relationships

Each entity may include attributes, which store information such as a name, a birth date, a designation, and so forth. The Objective-C object that corresponds to an entity expresses properties defined by these attributes.

Each entity may also define relationships, which are links between one object and another. These relationships can be single, using a one-to-one relationship (spouse, employer), or they can be multiple (children, credit card accounts), using a one-to-many relationship. In addition, relationships should be reciprocal, providing an inverse relationship (my child, his parent).

Select an entity to start adding attributes. With the entity selected, tap the Add Attribute button at the bottom right of the ...