The E-R (entity-relationship) data model views the real world as a set of basic objects (entities) and relationships among these objects.

It is intended primarily for the DB design process by allowing the specification of an enterprise scheme. This represents the overall logical structure of the DB.

• Entities and Entity Sets
• Relationships & Relationship Sets
• Attributes
• Mapping Constraints
• Keys
• Primary Keys for Relationship Sets
• The Entity Relationship Diagram
• Other Styles of E-R Diagram
• Reducing E-R Diagrams to Tables
  • Representation of Strong Entity Sets
  • Representation of Weak Entity Sets
  • Representation of Relationship Sets
• Generalization
• Aggregation
• Design of an E-R Database Scheme
  • Mapping Cardinalities
  • Use of Entity or Relationship Sets
  • Use of Extended E-R Features