What tools have you used to model data structures and processes? What specific diagrams did you draw?

For modeling data structures and processes, I use UML diagrams and specialized tools such as Enterprise Architect, Visual Paradigm, or draw.io.

The main diagrams I draw include:

• Class diagrams — for describing data structures, classes, and their relationships.
• Sequence diagrams — for illustrating interactions between objects over time.
• Use case diagrams — for describing functional requirements and user interactions with the system.
• Activity diagrams — for modeling business processes and workflows.
• Component and deployment diagrams — for architectural representation of the system.

Depending on the task, I may also use ER diagrams for database modeling or BPMN for complex business processes.