Entity-Relationship Diagram (ERD)

This entity-relationship diagram (ERD) sample shows an entity-relationship model for a school. It was designed on the base of the Wikimedia Commons file: Entity-Relationship-Modell.svg. [commons.wikimedia.org/ wiki/ File:Entity-Relationship-Modell.svg]
"An entity–relationship model (ER model) describes inter-related things of interest in a specific domain of knowledge. An ER model is composed of entity types (which classify the things of interest) and specifies relationships that can exist between instances of those entity types.
In software engineering an ER model is commonly formed to represent things that a business needs to remember in order to perform business processes. Consequently, the ER model becomes an abstract data model that defines a data or information structure that can be implemented in a database, typically a relational database." [Entity–relationship model. Wikipedia]
The Chen's notation ER-diagram example "Entity-relationship model" was created using ConceptDraw PRO software extended with the Chen Notation solution from the Software Development area of ConceptDraw Solution Park.

This ERD example was designed on the base of the entity-relationship diagram on the webpage "IS480 Team wiki: 2015T1 WhitePinnacle Documentation" from the Singapore Management University website. [wiki.smu.edu.sg/ is480/ IS480_ Team_ wiki%3A_ 2015T1_ WhitePinnacle_ Documentation]
This is ERD from the documentation of the High School Emergency Medical Responder (HS EMR) information system.
"Emergency medical responders are people who are specially trained to provide out-of-hospital care in medical emergencies. There are many different types of emergency medical responders, each with different levels of training, ranging from first aid and basic life support. Emergency Medical Responders have a very limited scope of practice and have the least amount of comprehensive education, clinical experience or clinical skills of EMS personnel. The Emergency Medical Responder (EMR) is not meant to replace the roles of Emergency Medical Technicians, Emergency Medical Technologists or Paramedics and their wide range of specialities. Emergency Medical Responders typically assist in rural regions providing basic life support where pre-hospital health professionals are not available due to limited resources or infrastructure." [Emergency medical responder. Wikipedia]
The example "Entity-Relationship Diagram" was drawn using ConceptDraw PRO software extended with the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.