Internal and External Data Models

Internal Model Database

The internal model represents a database in the perspective view of a database.
This model depicts a database as a collection of fixed-size records meaning that the database holds a fixed size.
It can be pretty close to the physical layer/ File structure.
It is the exact representation of the database.
It asks the designer to match it up to that of the conceptual model's characteristics and constraints.
Maps the conceptual model entities to the table present in the relational model.

The external model gives the user endpoint of view of the database.
When seen closer, this resembles the real-world scenario, or we can say related to that when observed by each user.
There may be a constraint within a database about certain information it presents.
For example, one user is not interested in the data of another users data.
An HR dept data is not interested in seeing data based on sales.
The external model subdivides the requirements and constraints that can be examined within their external model framework.
This means it divides between Hr dept and sales.

These are some of the basic stuff we need to know about internal and external data models.