Cardinality and Modality Essay

CardinalityCardinality indicates the utmost number of times an instance of one entity put forward be associated with instances in the related entity. Cardinality can subscribe to the values of one or many, no more detail than that. It is either one or more than one. On the relationship field, the cardinality is the closest to the entity box. The cardinality symbol in the diagram on the slide is in the inflammation circle. Cardinality is indicated at BOTH ends of the relationship line, so there is a left to right hand cardinality and a right to left cardinality.ModalityModality indicates the minimum number of times an instance in one entity can be associated with an instance in the related entity. Modality can have the values of zero or one, two or three are not allowed. The modality symbol is located next to the cardinality symbol, on the inside, i.e., NOT next to the entity box. A modality of one is denoted by a straight vertical line and a modality of zero is denoted by a ci rcle. Like cardinality, modality is indicated at both ends of the relationship.