Ø
«
»
0 : 3.4.11. Disjointness constraint
3.4.11. Disjointness constraint
Disjointness (d in circle) – single honours
Overlapping (o in circle) – joint honours/sports
Membership condition on same attribute
attribute-defined specialisation
defining attribute
implies disjointness
versus user-defined
each entity type specifically defined by user