How entities act upon each other or are associated with each other. For example, the named student might register for a course.
The two entities would be the student and the course, and the relationship depicted is the act of enrolling, connecting the two entities in that way.
I just loved the feeling.’Frimpong is dressed in a bright gold skin-suit with red and green stripes – the colours of the Ghanaian flag.
It’s seen more recently in the 19th and 20th Century works of philosopher-logicians like Charles Sanders Peirce and Gottlob Frege. Brown were working with close predecessors of Chen’s approach.
By the 1960s and 1970s, Charles Bachman (above) and A. Bachman developed a type of Data Structure Diagram, named after him as the Bachman Diagram.
ER diagrams also are often used in conjunction with data flow diagrams (DFDs), which map out the flow of information for processes or systems. Peter Pin-Shan Chen), currently a faculty member at Carnegie-Mellon University in Pittsburgh, is credited with developing ER modeling for database design in the 1970s.
While serving as an assistant professor at MIT’s Sloan School of Management, he published a seminal paper in 1976 titled “The Entity-Relationship Model: Toward a Unified View of Data.” In a broader sense, the depiction of the interconnectedness of things dates back to least ancient Greece, with the works of Aristotle, Socrates and Plato.
They also depict cardinality, which defines relationships in terms of numbers. Other examples: Customers who purchased last month, cars currently registered in Florida.