updated: 2022-01-23_12:32:31-05:00

updated: 2021-12-13_22:50:47-05:00

Referential Integrity

• The RI constraint is that a value appearing in one context must appear in another

Weak Entity

• Let weak entity set then the key consists of:

1. zero or more of it's own attributes and
2. key attributes from entity set are reached by certain many_to_one relationships from E to other entity sets

(supporting relationship)