Relationships and Subtypes
{"Image DocumentName": "Relationships and Subtypes", "Image ImageDescription": "Relationships at the supertype level indicate that all subtypes will participate in the relationship. The instances of a subtype may participate in a relationship unique to that subtype. In this situation, the relationship is shown at the subtype level (Fig. 3-3) Subtype entities inherit values of all attributes of the supertype. An occurrence of a subtype is also an occurrence of the supertype.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}