ONE throught MANY
ONE and ONLY ONE
- Two dashes it indicates that the first entity can have one and only one of the second
- specifically it cannot have zero,
- and it cannot have more than one
ZERO or ONE
- the first entity can have zero or one of the second, but not more than one
MANY to MANY
SOURCE: http://rapidapplicationdevelopment.blogspot.com/2007/06/entity-relationship-diagram-example.html
