48+ Design Er Diagram With Primary Key And Foreign Key Example Download Zip Background. A key is an attribute in er diagrams whose values are distinct for each individual entity in an entity set. In the er diagram the relationship between two strong entity set shown by using a.
• declare these elds as foreign keys.
Er diagrams don't necessarily show how data is manipulated, or the exact process it steps through, but if an attribute is used to identify the entity, it is the primary key and underlined. Frequently database designers will use pk or fk in the column name to easily identify a primary key or foreign key column. This can be described with the following er diagram: Foreign key is a field in a table.