Question

Data Modelling is the primary step in the process of database design. Compare and contrast Conceptual data model versus Physical data model. Illustrates with help of example to list down data (entities), relationship among data and constraints on data.

Answer 1

Conceptual Data Model

Physical Data Model

1. This model describes the contents of system. 2. This model is created by data architects and business stakeholders. 3. The purpose of this model is to organise data, define the scope and define business rules. 4.It defines the business objects and relationships between them. 5.Example, for a table named "Customer" and "Product", Customer and Product are defined as entities and relationship is shown between them with no cardinality in this model.

1. This model describes how the system will be implemented using a specific DBMS system 2. This model is created by developers and database administrators. 3. The purpose of this model is to implement the actual database. 4. It defines the actual design blueprint of a database. 5. For example, for tables named "Customer" and "product", this model defines the tables with all the attributes and their types and sizes. Also it defines the relationships among these tables.

Understanding what this model needs to define:

ERD Feature	Conceptual	Physical
Entity	To be defined	To be defined
Relationship	To be defined	To be defined
Column		To be defined
Column's type		To be defined
Primary Key		To be defined
Foreign Key		To be defined