Data Modelling and its Concepts

What is Data Modelling?

Data modeling (data modelling) is the process of creating a data model for the data to be stored in a database. The Data Model is a collection of concepts that can be used to describe the structure of a database -provides necessary means to achieve data abstraction.

There are two types of Data Modeling Techniques as follows:

1. Entity Relationship (E-R) Model --high level Conceptual data Model.
2. UML (Unified Modelling Language) --Object Modeling methodologies.

Types of Data Models:

 There are mainly 3 types of data models as described below.

• Conceptual Data Model: This Data Model defines WHAT the system contains. This model is typically created by Business stakeholders and Data Architects. The purpose is to organize, scope and define business concepts and rules.

            The 3 basic tenants of Conceptual Data Model are.

                Entity: A real-world thing

                Attribute: Characteristics or properties of an entity

                Relationship: Dependency or association between two entities

• Logical Data Model: Defines HOW the system should be implemented regardless of the DBMS. This model is typically created by Data Architects and Business Analysts. The purpose is to develop technical map of rules and data structures.

• Physical Data Model: This Data Model describes HOW the system will be implemented using a specific DBMS system. This model is typically created by DBA and developers. The purpose is actual implementation of the database.

Pros of Data Models:

• The main goal of a designing data model is to make data objects offered by the functional team are represented accurately and detailed enough.
• The information in the data model can be used for defining the relationship between tables, primary and foreign keys, and stored procedures.
• Data Model helps business to communicate the within and across organizations.

Cons of Data model:

• To develop Data model, one should have knowledge of physical data and storage characteristics.
• Even smaller change made in structure require modification in the entire application.
• There is no set data manipulation language in DBMS.