ENTITY RELATIONSHIP MODELLING

ENTITY RELATIONSHIP MODELLING

1. 3 Basic Concepts of E-R Model

   • entity type
     • strong entity
     • weak entity
   • attributes
     • candidate key
     • composite key
     • primary key
   • relationship type
     • weak relationship
     • strong relationship

2. Structural Constraints

   • cardinality constraints
     • one to one relationship
     • one to many relationship
     • many to many relationship
   • participation constraints
     • total (mandatory)
     • partial (optional)