In ER digram we have an assignment and our teacher forces us to use at least an IS-A relation, i Just wonder if it is possible for an entity to have is-a relationship with another entity but do not have any attribute ? For example:
An actor ISA cast.
Cast have a name.
all i need from the actor is to have a name, no date of birth, telephone number or etc.
I also attached my diagram can someone say if it have any problem or not.
P.S. we MUST use at least one ISA relation we may not use primary key,
Number of downloads: 135