10
(Source:
Whitten,
Jeffry
L., Bentley,
Lonnie
D., and Dittman,
Kevin
C. 2000.
System Analysis
and Design
Methods)
2.1.3.1.3 Relationship
According to Whitten [4], a
relationship
is
an
association
that
exists
between
one
or
more entities. The relationship may represent an event that links the entities. The
following figure is an example of a relationship.
Figure 2. 4 Relationship
(Source: Whitten, Jeffry L.,
Bentley, Lonnie D., and Dittman, Kevin C. 2000. System Analysis and Design
Methods)
2.1.3.1.5 Cardinality
According to Whitten [4], cardinality defines the
minimum
and the
maximum
number of occurrences of one entity
that
may be
related to other entity. Cardinality
must
be defined in both directions for every relationship, because all relationships are
bidirectional. The examples of cardinality symbols are demonstrated in Figure below.
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