SS2 First Term Data Processing Lesson Note – Types of Data Models

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WEEK TWO                                                                         

TOPIC:  TYPES OF DATA MODELS

CONTENT: 

• Definition of Data Model
• Type of data model

SUBTOPIC 1:   Definition of Data Model

Data Models are fundamental entities to introduce abstraction in a DBMS. Data models define how data is connected to each other and how they are processed and stored inside the system.

A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to properties of the real-world entities. For instance, a data model may specify that the data element representing a car be composed of a number of other elements which, in turn, represent the color and size of the car and define its owner.

THREE LEVELS OF DATA MODEL

The ANSI/SPARC three level architecture

1. Conceptual Data model
2. Logical Data Model
3. Physical Data Model

Conceptual Data Model:  is a technology independent specification of the data to be held in the database. It is the focus of communication between the data modeler and business stakeholders, and it is usually presented as a diagram with supporting documentation.

Logical Data Model: is the translation of the conceptual model into structure that can be implemented using a database management system (DBMS).

This model specifies tables and columns. These are the basic building blocks of relational databases, which are implemented using a relational database management system (RDBMS)

Physical Data Model: this incorporates any changes necessary to achieve adequate performance and is also presented in terms of tables and columns, together with a specification of physical storage and access mechanisms.

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