Entity-Relationship Model (ER)

Entity-Relationship Model (ER)

1. Fundamentals of ER Constructs

   • Basic Objects
     • Entities
       • Are the principal data objects about which information is to be collected
     • Relationships
     • Attributes and Keys
     • Weak Entities
   • Degree of a Relationship
   • Attributes of a relationship
   • Existence of an Entity in a Relationship
   • Alternative Conceptual Data Modeling Notations

2. Advanced ER Constructs

   • Generalization
     • Supertypes
     • Subtypes
   • Aggregation
   • Ternary Relationship
   • General n-ary Relationship
   • Exclusion Constraint
   • Foreign Keys and Referential Integrity
     • is an attribute of an entity or an equivalent SQL table