CO2401 Software Development Lecture 4 Notes

CO2401: Software Development
Lecture 4

Conceptual Model
1. Purpose of a Conceptual Model
o The conceptual model captures all relevant information about the
system domain as provided in the requirements document.
o It forms the basis for the system’s structure by identifying:

 Relevant entities
 Attributes
 Associations
 Multiplicities
 Invariants
2. Points to Remember
o Domain modelling is not an exact science; different teams may
produce different models based on how they interpret the
requirements.
o Even with the same classes and associations, UML class diagrams
can be represented differently (e.g., a property could be an attribute
or an association).
Identifying Associations
1. Representing Relationships
o Associations in a class diagram represent the relationships between
entities.
o Example:

 Customer hires a Car
 Multiple representations might be used depending on
whether the relationship itself holds additional information,
such as loan dates.
2. Handling Relationships with Information
o When a relationship holds information (e.g., loan date), an
additional class (e.g., Loan) can be introduced to capture this
information.