4-eermodel.htm; updated 1/9/01

ENHANCED E-R MODEL
and BUSINESS RULES

Introduction.

GENERALIZATION HIERARCHY -- Subtypes and Supertypes.

Attribute Inheritance and Primary Keys for Generalization Hierarchies.

When to Use a Subtype.
 
SPECIFYING CONSTRAINTS
 
Completeness Constraint.
Disjointness Constraints. Subtype Discriminators. Supertype/Subtype Hierarchies.  
BUSINESS RULES
 
Overview. Entity Integrity (Uniqueness Integrity). Referential Integrity. Domain Constraint. Operational Constraint. CREATE ASSERTION Faculty_Load
  CHECK (SELECT Count(*)
    FROM ASSIGNED
    WHERE Faculty_ID = 'BOCK') <= 12;
 
 
 
Triggering Operations.

END OF NOTES.