**A simplified description of things and how they relate to one another used in software engineering and business.** An entity relationship model ("ER Model") is a simplified description of what "entities" exist (see: [[Entity Definition]]) and how they are related to one-another ([[Entity Relationship Categories]]). They are useful in Software & Systems Engineering, in business, and potentially useful in any other domain of study. Interestingly, there isn’t really a [[UML]] ‘Entity Relationship’ diagram - but they use [[Class Diagrams]], which are similar.. Entity relationship models name independent entities and describe how they relate to one-another via relationships, which themselves can be named, that may or may not be subject to constraints. Common relationship constraints include "cardinality" and also "role/type acceptance". There are a number of competing [[Entity-Relationship Modeling Standards]]. I tend to like either Crow’s Feet Notation or the even simpler yet more descriptive Min-Max pairing. ![[Untitled 29.png]] **** # More ## Source [Entity-relationship model](https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model) ## Related - [[Entity Definition]] - [[Relational Databases]] - [[Cardinality]] - [[Entity-Relationship Modeling Standards]] - [[IDEF1X]] - [[Diagram Types (index)]]