What represents the structure and nature of the data being dealt with?

The structure and nature of the data being dealt with is represented by an object type. An object type defines the schema for an object within a system, including the attributes it contains and their respective data types. It establishes the rules and relationships for how data is organized, accessed, and manipulated within the application.

By defining an object type, developers can ensure that data can be consistently validated and processed, providing a clearer understanding of what kind of data the application is handling and how different pieces of data relate to one another. This is foundational for creating robust applications that can effectively manage and utilize data.

In contrast, while an object and property type relate to specific instances or attributes of data, they do not provide a comprehensive structure like an object type does. A join table is a specific implementation detail used in database design for creating many-to-many relationships between entities, but it is not a representation of the overall structure and nature of the data.