Information Requirement Analysis

Explain importance of FDD & E-R Diagram.

• FDD is a functional Decomposition Diagram.
• It is the process of breaking a complex entity into smaller sub parts and this complex entity is broken down until the structure of entities are in an understandable structure.
• It means breakdown of an item into groups on the basis of function of an item perform.
• A decomposition diagram shows a high level function, process, organization, object that are broken down to lower level.

• It is useful in the analysis of processes by breaking them down into smaller components.
• The analyst breaks down the process into sub-processes, functions, rules, decisions to make them more understandable.
• Decomposition of process helps the project team to clearly specify whether the function is in scope or not.
• Identify the current system function from undocumented system and replaced with the documented system.
• Decomposition is an analytical technique and it is commonly used by the business analyst.
• Business analyst decomposes things like system into process, function, rule and decision. Processes into steps,decision. Goals into sub goal and objective. Requirements into functional requirement, non functional requirement, business rule, decision and constraint.
• Structural decomposition are the physical component, logic object, attribute, field or arrangement of structure within a design.
• Functional decomposition is a good process for the people and easily understood by the customer.
• It helps to find duplicate or overlapping activities.
• Decomposition breaks complex system into separate components and it helps with scope, development and planning.
• The simplicity of the structure and representation helps to understand the function and process.

• An entity relationship diagram is a visual representation of data and by using conventions they describe how data are related to each other.
• For example: Student is an entity and Name, Roll_no., Birth_date are the attributes.

• An entity can be a person, place, event or object that is related to a given system.
• Entities are represented in ER diagrams by a rectangle and name as singular nouns.
• For example, for school system include entities student, teachers, subject, fees, roll number etc.
• Following figure shows an example of a student. A student is an entity and Name, Roll_no., Birth_date are the attributes of a student. An entity student is represented in the rectangle and attributes are in an ellipse.

• E-R diagram form is a very useful framework for creating and manipulating databases.
• It is easy to understand and does not require any large training to understanding its working process.
• The designer uses an E-R diagram to easily communicate with a developer, a customer and user.
• E-R diagrams are readily translatable into relational table which is used to quickly build a database.
• It is directly used by database developers as the blueprint for implementing data in specific software application.
• It is used to describe the different relationship and operation within an organization.
• It is a graphical and diagrammatic representation of an entity and helps for better understanding.
• It is important for a website owner to get the relationship between data and picture functionality for a need of a website.
• It reduces the development time and help to meet deadlines and save money.