Download Design Er Diagram Derived Attribute Example Download Zip PNG. An er diagram shows the relationship among entity sets. Designing an er diagram consider the following set of requirements for a university database.
Design choice for er conceptual model it is very difficult to determine if a particular concept must be represented as entity type or 67.
An example of database design and description using the model and the diagrammatic technique is given. 22 employee derived attributes name emp_no salary age birth date instructor: The er format allows one to describe a relational schema in terms of its entities (tables), attributes (columns). When you have a column where it's value could be calculated from another column.