Information Modeling and Relational Databases, 2nd Edition

Chapter Notes

In contrast to our usage, occurrence frequencies are sometimes defined as the number of times members of an object type population must play a role—frequencies of 0 are then allowed and mean optional. Ring constraints are often discussed in logic books, within the context of the theory of dyadic relations, but are rarely discussed in modeling approaches other than ORM. Some extended versions of intransitivity were introduced by Peter Ritson.