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

The data modeling is said to be the primary step in database design, this is because this modeling is used to give the abstract of the design phase, the design outputted by data modeling is called the conceptual design. So, as the modeling gives the abstract design it is known as the primary step.

The difference between physical and conceptual model is given as follows:

The physical model of the database is the lowest model, also it is used to give the physical representation. The model at the physical level is managed by the operating system, it basically deals with the storage of the data in the memory of the system.

The conceptual model on the other hand is the logical view of the entire database. It is used to show constraints among the relationships in the database, also as it gives the view of the entire database it also is the collection of all the entities of the database.

Th examples are given as follows:

The example of entities are: children, teachers, subjects

the relationship example is: The children are guided by teachers, also the teacher teaches the subject

the constraints examples are: Each student has subject with the highest and lowest grade.

So, above give the example entities, relationships, and also constraints on the data.

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