Dr. Peter Pin-Shan Chen (Chinese: 陳品山) is an American computer scientist and Professor of Computer Science at Louisiana State University, who is known for the development of Entity-Relationship Modeling in 1976.
Everything is obvious once you know the answer. The paperclip looks simple only because someone else did the hard work to invent it. The same applies to the Entity Relationship Diagram (ERD).
In the mid-1970s, databases were getting bigger, more complex, and harder to explain. Business users didn't speak the same language as database designers. Developers struggled to describe data structures in a way that made sense to non-technical stakeholders. It is coincidentally the same problem we have 50+ years later.
Peter Pin-Shan Chen, then an assistant professor at MIT, saw the communication gap and decided to solve it.
In 1976, he published "The Entity-Relationship Model — Toward a Unified View of Data" in "ACM Transactions on Database Systems"
He wanted to create a universal visual language that could describe any data in a way humans could easily understand, before worrying about the technical implementation.
It was a really simple, elegant solution that consisted of three simple building blocks:
The things or concepts we care about (e.g., Customer, Order).
The properties of those things (e.g., Customer Name, Order Date).
How those things are connected (e.g., Customer places Order).
With this, a business analyst and a database engineer could point to the same diagram and agree on what was being modelled, long before a single line of SQL was written. Before Chen, data modelling often lived buried in technical schemas or scattered documentation. Chen's ERD:
Bridged business and technology: Everyone could see the same map.
Abstracted away the storage layer: The model was logical, not tied to a specific DBMS.
It made data modelling visual, collaborative, and portable.