Inf2603 Assignment 02 (Quiz & Answers) Due 13 June 2025 Databases I

INF2603
Assignment 02 (QUIZ)
Due 13 June 2025
DATABASES I

, DATABASES I

INF2603

Assignment 02 (QUIZ)

Due Date: 13 June 2025




Entity-Relationship (ER) Modeling

Entity-Relationship (ER) modeling is a foundational methodology in database design,
providing a structured approach to represent real-world entities, their attributes, and
relationships. It serves as a blueprint for constructing robust and scalable databases.




4-1: Main Characteristics of Entity-Relationship Components

The ER model comprises three primary components—entities, attributes, and
relationships—each with distinct characteristics that underpin effective database design.

• Entities:

• An entity represents a real-world object or concept that can be distinctly
identified, such as a "Student" or "Course" in a university database (Elmasri
& Navathe, 2016).

• Characteristics:

• Uniqueness: Each entity instance must be uniquely identifiable,
typically via a primary key (e.g., "Student_ID").

• Persistence: Entities represent objects with a stable existence in the
database, distinguishing them from transient data (Connolly & Begg,
2015).

• Types: Entities can be strong (independent, e.g., "Department") or
weak (dependent on another entity, e.g., "Dependent" linked to
"Employee") (Teorey et al., 2011).