Arrows are one of the main Diagram Semantic Mechanisms. They can be used in lots of different ways to mean lots of different things, but all those potential meanings essentially boil down to two (or three) top-level categories - relational & flow (and sequence).
Arrow Meaning Types
Relational
See: Entity Relationship Categories for a more complete list.
- Composition
- Association
- Generalization/specialization
- Labeled relationship
- Constraint
Flow
- Object/energy flow
- Data/information flow
Sequence
- This thing follows that thing, this is sort of like a flow & relationship at the same time, but a function with Arity = 3 (to, from, and context)
- State/phase changes
Arrow Syntax
Different Diagram Types (index) will use arrows for different (and potentially multiple) things, using different syntaxes. Unfortunately there is no such thing as a universal syntax, although there are some common conventions. I cover these in my Entity Relationship Categories note.
Source
- self