Multiplicity of Relationships Many-many Many-one One-one In a many-many relationship,an entity of either set can be connected to many entities of the other set.E.g.,a bar sells many beers;a beer is sold by many bars. In a many-one relationship,each entity of the first set is connected to at most one entity of the second set.But an entity of the second set can be connected to zero,one,or many entities of the first set. In a one-one relationship,each entity of either entity set is 12 related to at most one entity of the other set.12 Multiplicity of Relationships Many-many Many-one One-one • In a many-many relationship, an entity of either set can be connected to many entities of the other set. E.g., a bar sells many beers; a beer is sold by many bars. • In a many-one relationship, each entity of the first set is connected to at most one entity of the second set. But an entity of the second set can be connected to zero, one, or many entities of the first set. • In a one-one relationship, each entity of either entity set is related to at most one entity of the other set