An Entity Relationship Diagram variant.
IDEF1X is a lesser-used technology-independent Entity-Relationship diagramming method. It displays Entities, their properties, and the relationships between them. It includes constructs for several things beyond simple database diagrams, such as classification relationships, and “Views”, which are defined subsets if the whole model illustrating some purpose.
Incomplete list of IDEX1X features:
- bidirectional link labels
- Link multiplicity - but in a less intuitive syntax
- Identifiers - a confusing construct
- Classification relationships - children are a type of parent
Originally that list had pictures. But they broke and nobody uses IDEF1X.