Describe The Categories Of The Data Models?

We can categorize data models according to the type of concepts they used. There are three types of data models.
(1) High level or conceptual data models.
(2) Low level or physical data models.
(3) Representational or implementation data models.

* Concepts like entities, attributes, and relationships are included in conceptual data models. Entity is a thing in real world with an independent existence. We can also define entity as a real world object or concept. An attribute is used to describe entity. A relationship among two or more entities represents an association between them. Example of this is works-on relationship between an employee and a project.

* Low level or physical data models provide the details about how the data is stored in a computer. Concepts which low level data provide are generally used by computer specialist. End users cannot understand those concepts easily.

* Representational or implementation data models are mostly used in commercial Database management Systems. End users can understand the Concepts provided by Representational or implementation data models.  This model is different from physical data model as it hides some details about data storage. Representational data models are also called record based data models because they represent data by using record structure.