The document discusses database design, detailing its phases: conceptual, logical, and physical design, along with the importance of understanding user requirements in systems analysis and development. It outlines traditional and iterative approaches to system development, specifically emphasizing the waterfall model and its potential pitfalls, such as miscommunication of requirements. Additionally, the document introduces prototyping as a method for gathering user feedback during the development process.

1. Er. Nawaraj Bhandari
Topic 9
Database Design

2. Database Design
 Database Design means moving from a set of requirements to
implementing these with database technology.
Moving from a set of requirements
Database Technology

3. Phases of Database Design
 Conceptual design
 Logical design
 Physical design

4. Conceptual Database Design
 Investigation of data needed to support system
 Does not take account of physical implementation or data model
What data is held?
In what format is the data?
How is this the data
used?

5. Logical Design
 Data is investigated and design is undertaken without regard to the
DBMS product that will be used, but that data model (usually the
relational model) is known.
Normalisation Entity relationship diagram
Design transactions

6. Physical Design
 From entities to tables
 Designing the base relations
Indexing Denormalisation
Query tuning
View creation

7. Case Tools
 Computer Aided Software Engineering tools
 Design tools: Visio
 Documentation tools : Word processing software
 Code generators : Mysql Workbench, Sql developer, Sql server
management studio etc.

8. Systems Analysis & Development
 Systems Analysis
The art of understanding and documenting the requirements of a
given set of users within the context of an organization.
 Systems Development
The development of the whole system from beginning to end. This
might include a database, applications, a network etc.

9. Approaches to System Development
 There are many different approaches to systems development.
1. Traditional systems development lifecycle (SDLC) or ‘waterfall’
approach
2. Iterative approaches. Eg. Agile
 Understanding requirements is vital to being able to produce a
finished system that meets the business needs of an organization.

10. Waterfall Approach

11. Waterfall Approach
 Traditional systems development lifecycle (SDLC)
 Also known as Generic(Common) Systems Development Lifecycle
 This involves a complete set of steps that a team follows.
 The fundamental idea is to divide the development process into a
series of phases or stages, each of which finishes before the next one
starts.
 This process is often viewed as a cascade of steps, which is why it has
been called the waterfall approach.

12. Waterfall Approach
1. Strategy and planning
2. Feasibility study
3. Systems analysis (or analysis)
4. Design
5. Implementation
6. Maintenance

13. Problems with Waterfall Approach
 Users have not communicated requirements properly
 Users have not understood their own needs
 Analyst misunderstood
 Omission

14. Prototypes and Prototyping
 Prototype – a first or original example of something from which others
have or will be developed
 Prototyping – the process whereby a model is built of part of the
system and user feedback on it is gathered. Part of the requirements
gathering process
 Note: a prototype is a thing. Prototyping is something we do.

15. Iteration

16. ANY QUESTIONS?