What is a formal method of describing data and data relationships called?

A formal method of describing data and data relationships is known as a data model. Data models serve as a theoretical framework that outlines how data is structured and organized, defining the relationships between different data entities. They provide a visual representation and a conceptual blueprint that helps database designers understand how data systems can be organized and structured.

Data models can take various forms, including entity-relationship diagrams or UML diagrams, and they help in establishing guidelines for the data types, attributes, and constraints that the database will enforce. By using a data model, developers and data architects are able to effectively plan and communicate the intended structure and behavior of the database, ensuring compatibility with the requirements of the application and the needs of the users.

In contrast, a data dictionary refers to a detailed repository of metadata, describing the attributes, relationships, and meaning of the data within a system rather than a model of the data structure itself. A database management system (DBMS) is software that enables the creation and management of databases but does not describe the data or relationships formally. A data schema, while related, is more about the specific implementation and organization of the database structure rather than a conceptual framework for data relationships.