Schema.org Basics

Schema.org is a collaborative, community activity with a mission to create, maintain, and promote schemas for structured data on the Internet, on web pages, in email messages, and beyond.

Classes and Properties

Everything in Schema.org schema is either an item type/class or a property. For example, Person is a schema.org Class. Every Class has its own properties. For example, Address is a schema.org Property.

Hierarchical Structure

All classes in Schema.org schema is defined in a hierarchical tree structure. Thing is the root of this structure. And all classes besides Thing will have its own parent class(es) and may also have its own child class(es). For example, Patient is a subclass(child) of Person and Person is a subclass(child) of Thing.

Moreover, properties could also have parent properties. For example, isbn is a subproperty(child) of identifier.

Inheritance

All classes defined in Schema.org schema will have its own specific properties. For example, Address is a property of Person. In addition, all classes will inherit the properties of its ancestors. For example, description is a property of Thing. And since Person is a subclass(child) of Thing, Person inherit the property description from its parent Thing.