INF2603
Assignment 03 (QUIZ)
DUE 01 July 2025
DATABASES I
, DATABASES I
INF2603
Assignment 03
Due Date: 01 July 2025
Advanced Data Modelling
Data modeling is a cornerstone of database design, enabling the structured representation
of real-world entities and their relationships. The Extended Entity-Relationship (EER) model
builds upon the foundational Entity-Relationship (ER) model, introducing advanced
constructs to address complex data requirements.
5-1: Main Extended Entity-Relationship (EER) Model Constructs and Their
Representation in ERDs and EERDs
The EER model extends the ER model by incorporating advanced constructs such as
specialization, generalization, categorization, and aggregation, enabling more expressive
and precise data modeling. These constructs are visually represented in ER Diagrams
(ERDs) and Extended ER Diagrams (EERDs), which serve as blueprints for database design.
• Specialization and Generalization:
• Definition: Specialization involves defining subclasses (subtypes) from a
superclass (supertype) based on distinguishing attributes, while
generalization consolidates multiple entity types into a single supertype. For
example, an "Employee" supertype may specialize into "Full-Time" and "Part-
Time" subtypes.
• Representation: In EERDs, a circle labeled with a subset symbol ( ⊂ )
connects the supertype to its subtypes. A disjointness constraint (d)
indicates mutually exclusive subtypes, while an overlapping constraint (o)
allows entities to belong to multiple subtypes (Elmasri & Navathe, 2016).
• Critical Engagement: Specialization enhances modularity but increases
complexity in query processing. For instance, querying a supertype requires
consideration of all subtypes, which can impact performance in large
databases (Teorey et al., 2011).
Assignment 03 (QUIZ)
DUE 01 July 2025
DATABASES I
, DATABASES I
INF2603
Assignment 03
Due Date: 01 July 2025
Advanced Data Modelling
Data modeling is a cornerstone of database design, enabling the structured representation
of real-world entities and their relationships. The Extended Entity-Relationship (EER) model
builds upon the foundational Entity-Relationship (ER) model, introducing advanced
constructs to address complex data requirements.
5-1: Main Extended Entity-Relationship (EER) Model Constructs and Their
Representation in ERDs and EERDs
The EER model extends the ER model by incorporating advanced constructs such as
specialization, generalization, categorization, and aggregation, enabling more expressive
and precise data modeling. These constructs are visually represented in ER Diagrams
(ERDs) and Extended ER Diagrams (EERDs), which serve as blueprints for database design.
• Specialization and Generalization:
• Definition: Specialization involves defining subclasses (subtypes) from a
superclass (supertype) based on distinguishing attributes, while
generalization consolidates multiple entity types into a single supertype. For
example, an "Employee" supertype may specialize into "Full-Time" and "Part-
Time" subtypes.
• Representation: In EERDs, a circle labeled with a subset symbol ( ⊂ )
connects the supertype to its subtypes. A disjointness constraint (d)
indicates mutually exclusive subtypes, while an overlapping constraint (o)
allows entities to belong to multiple subtypes (Elmasri & Navathe, 2016).
• Critical Engagement: Specialization enhances modularity but increases
complexity in query processing. For instance, querying a supertype requires
consideration of all subtypes, which can impact performance in large
databases (Teorey et al., 2011).
