LIS 558 - Entity-relationship diagrams in Kroenke
shows a version of entity-relationship diagrams
that differs in some respects
from the classic conventions of Chen and Jackson.
Most of the correspondences are fairly obvious.
One difference that may cause some difficulty
is the addition of a notation for "minimum
The point is almost always
whether the minimum cardinality of an entity type in a
is zero or not
(indicated respectively by an oval
or by a crossing line).
from the minimum cardinality of one entity type in a
we can predict whether occurrences of the other entity
- if the minimum cardinality is zero,
occurrences of the other entity type are not
- if the minimum cardinality is not zero,
occurrences of the other entity type are
says, among other things,
that every course requires at least one faculty member to teach
From this, we can predict
that every course must participate in the relationship
of being taught by a faculty member,
which would translate into the following form in the classic
*Kroenke, D.M. 2000.
fundamentals, design & implementation,
Last updated July 5, 2001.
This page maintained by
Prof. Tim Craven
E-mail (text/plain only): firstname.lastname@example.org
Faculty of Information and
University of Western
Canada, N6A 5B7