Design of an E-R Database Scheme

The E-R data model provides a wide range of choice in designing a database scheme to accurately model some real-world situation.

Some of the decisions to be made are

• Using a ternary relationship versus two binary relationships.
• Whether an entity set or a relationship set best fit a real-world concept.

• Whether to use an attribute or an entity set.

• Use of a strong or weak entity set.

• Appropriateness of generalization.

• Appropriateness of aggregation.

• Mapping Cardinalities
• Use of Entity or Relationship Sets
• Use of Extended E-R Features