Database Design Concepts: The Complete Steps.

Objectives:

• What is Database Designing?
• What is the need of Database Designing?
• What are the various steps in Database Designing.

What is Database Designing?

It is a process of developing a detailed data model of a database.

Data Model :

It's an abstract model which

• Documents and organizes the business data for communication between functional and technical people and between team members and is used as a plan for developing applications, specifically how data are stored and accessed.

 What is the need of Database Designing?

A simple and straight answer for this can be :Why would you need a blueprint before building a house?
Still we will explore the necessity of database designing.

• Database design refers to the activities that focus on the design of the database structure that will be used to store and manage end-user data.
• A well-designed database facilitates data management and generates accurate and valuable information. 
• A poorly designed database is likely to become a breeding ground for difficult-to-trace errors that may lead to bad decision making—and bad decision making can lead to the failure of an organization.
• In fact, database design is such a crucial aspect of working with databases that most of this book is dedicated to the development of good database design techniques.
• College students study database design, why organizations of all types and sizes send personnel to database design seminars, and why database design consultants often make an excellent living.
• In short "Even the best DBMS will perform the worst with a badly designed database."

What are the various steps in Database Designing?

The process of database design is divided into different parts. It consists of a series of steps.They are

• Requirement Analysis
• Conceptual Database Design (ER-Diagram)
• Logical Database Design (Tables, Normalization etc)
• Physical Database design (Table Indexing, Clustering etc)

Requirement Analysis

In this phase a detailed analysis of the requirement is done.The objective of this phase is to get a clear understanding of the requirements.It make use of various information gathering methods for this purpose. some of them are

• Interview
• Analyzing documents
• Survey
• Site visit
• Joint Applications Design (JAD) and Joint Requirements Analysis (JRA)
• Prototyping 

Conceptual Database Design (ER-Diagram)

The requirement analysis is modeled in this conceptual design. The ER Model is used at the conceptual design stage of the database design.The ER diagram is used to represent this conceptual design. ER diagram consists of Entities, Attributes and Relationships.

Logical Database Design (Tables, Normalization etc)

Once the relationships and dependencies are identified the data can be arranged into logical structures and is mapped into database management system tables. Normalization is performed to make the relations in appropriate normal forms.