Alright, the exercise: Suppose we wish to keep a genealogy. We shall have one entity set, people. The info we wish to record about persons includes their name (an attribute) and the following relationships: mother, father, and children. Give an E/R diagram involving the people entity set and all the relationships in which it is involved. Include relationships for mother, father, and children; Do not forget to indicate roles when an entity set is used for more than one relationship. So what I drew seems too simple: An entity box called people, which has connected the attribute of name. Then the "motherof" relationship which loops back into the people entity. Then the "fatherof" relationship which loops back into the people entity. Then the "childof" relationship which loops back into the people entity, on the loopback I used the notation of a double line with the number 2, specifying that a child is related to 2 persons(aka parents). For some reason it doesn't seem right though, and thoughts?