The mapping of orders to items is many to many (n:m) because each
Moving on to product and order, a product can be associated with zero or many orders, while an order must have one or many products (you can't ...
all of employees: you want to model the relationships between managers and their subordinates ...
Peter Chen, who developed entity-relationship modeling and
interfaces into one consolidated logical database model. 3.
of an independent entity include the Customer table, Employee table or Product table. ... It is minimal because every column is necessary in order to attain uniqueness.
ORDER - One or more products purchased by a customer. OrderID *; OrderDate.
UML gives us a way to model relationship attributes by showing them in an ...
metrics for Entity-Relationship (ER) diagrams, which are a relevant graphical formalism of the
The second relationship we will turn around so it has the same entity order as the ... In an ERD (see next chapter) this type of relationship is a line that goes out of ...