CSC 742 Database Management Systems Phases ... - Dr. Peng Ning
CSC 742 Database Management Systems Phases ... - Dr. Peng Ning
CSC 742 Database Management Systems Phases ... - Dr. Peng Ning
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Why Do We Need EER<br />
ER modeling is sufficient for representing<br />
many database schemas for “traditional”<br />
database applications.<br />
Recent applications require additional<br />
semantic data modeling concepts<br />
Class/subclass relationship<br />
Type inheritance<br />
Specialization and generalization.<br />
Spring 2002 <strong>CSC</strong> <strong>742</strong>: DBMS by <strong>Dr</strong>. <strong>Peng</strong> <strong>Ning</strong> 23<br />
Subclass-Superclass<br />
Subclasses:<br />
Further refinement (grouping) of a<br />
(super)class<br />
Attributes are inherited<br />
Class/subclass relationship is different<br />
from the relationship in ER modeling.<br />
Spring 2002 <strong>CSC</strong> <strong>742</strong>: DBMS by <strong>Dr</strong>. <strong>Peng</strong> <strong>Ning</strong> 24<br />
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