Database Reference
In-Depth Information
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INDIVIDUAL
INSTITUTIONAL
Figure 6-23
Total specialization.
STUDENT
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GRADUATE
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Figure 6-24
Partial specialization.
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Exclusive, partial specialization
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Nonexclusive, partial specialization
SPECIAL OBJECT TYPES AND RELATIONSHIPS
We have discussed various examples of objects and their relationships. The object
sets you represent by a rectangular box in a data model diagram are all business
objects relevant to the information requirements of the real world portrayed by the
model. You have also noted, through many examples, that instances of one object
may have associations with instances of another object. If so, you draw lines con-
necting the two associated objects, indicating the relationship by a diamond shape
in between with the name of the relationship written inside the diamond. By now,
you know all of this clearly.
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