· Data
Modeling - Conceptual, Logical, And Physical Data Models
·
The three levels of data modeling, conceptual data model, logical data model, and physical data model, were discussed in prior sections. Here we compare these
three types of data models. The table below compares the different features:
|
Feature
|
Conceptual
|
Logical
|
Physical
|
|
Entity Names
|
✓
|
✓
|
|
|
Entity Relationships
|
✓
|
✓
|
|
|
Attributes
|
|
✓
|
|
|
Primary Keys
|
|
✓
|
✓
|
|
Foreign Keys
|
|
✓
|
✓
|
|
Table Names
|
|
|
✓
|
|
Column Names
|
|
|
✓
|
|
Column Data Types
|
|
|
✓
|
·
· We can see that the complexity
increases from conceptual to logical to physical. This is why we always first
start with the conceptual data model (so we understand at high level what are
the different entities in our data and how they relate to one another), then
move on to the logical data model (so we understand the details of our data
without worrying about how they will actually implemented), and finally the
physical data model (so we know exactly how to implement our data model in the
database of choice). In a data warehousing project, sometimes the conceptual
data model and the logical data model are considered as a single deliverable.
