<Li> a thick line indicates both, i.e. bijectivity: each entity in the entity set is involved in exactly one relationship . </Li> <Li> an underlined name of an attribute indicates that it is a key: two different entities or relationships with this attribute always have different values for this attribute . </Li> <P> Attributes are often omitted as they can clutter up a diagram; other diagram techniques often list entity attributes within the rectangles drawn for entity sets . </P> <P> Related diagramming convention techniques: </P>

What are the different types of relationship notations idfix ie iex both idfix and ie