Meanings of ERD Symbols - Intergraph Smart Instrumentation - - Reference - Hexagon PPM

Intergraph Smart Instrumentation Entity Relationship Diagrams (2019)

Intergraph Smart Instrumentation

Connecting lines between entities indicates a relationship exists between the entities. The degrees of relationship (cardinality) are displayed by the symbols next to the entities on the connecting relationship line.

Indicates: one or zero.

Indicates: zero or many.

Indicates: one and only one.

Indicates: one or many.

A closed arrow next to an entity indicates an inheritance relationship. In the example below, the closed arrow indicates that the Analyzer, Relief_Valve, Pressure, and so forth, inherits structure and behavior from the Process Data General entity.