: Represented as rectangles, these are the "nouns" of the system, such as Customer , Order , or Product .
: They provide a common visual language for stakeholders, business analysts, and engineers to discuss data requirements. AZ erdЕ‘rЕ‘l
: Adds more detail, defining attributes and keys but remaining independent of a specific database technology. : Represented as rectangles, these are the "nouns"
: They act as a blueprint for developers to build the actual physical database. : Represented as rectangles
