Data Structure and Elements

Data Structure

• A data structure is a group of data elements handled as a unit.

Finalizing Design Specifications

• The process of finalizing design specifications involves taking logical design information and turning it into a blueprint for the physical information system.
• It can be paper-based or computer-based, and can be written, graphical, or a combination of both.
• The format and amount of detail will be driven by the intended audience.
• Good specifications should be stated simply, completely, unambiguous, and have attributes that make requirements more understandable.

Traditional Projects

• Deliverables for traditional projects include a set of physical design specifications for the entire system, including detailed specifications for each separate part of the system.
• Functional descriptions are included for each part of the system, along with input received and output generated for each program and its component parts.
• Complete design specification is comprehensive and can be based on traditional methods or Agile methodologies.

Specification Documents

• Specification documents contain an overall system description, interface requirements, system features, nonfunctional requirements, and other requirements.
• They also include supporting diagrams and models.
• Computer-based requirements management tools make it easier to keep documents up to date, add additional requirements, and link related requirements.

Structure Chart

• A structure chart is a hierarchical diagram that shows how an information system is organized.
• It shows how an information system is organized in hierarchical models and how parts of a system are related to each other.
• It also shows the breakdown of a system into programs and internal structures of programs written in third- and fourth-generation languages.

Prototyping and CASE Tools

• Prototyping is used to capture design specifications, and can be evolutionary or throwaway.
• Evolutionary prototyping involves modeling parts of the target system and evolving the remaining system from the prototype.
• Throwaway prototyping involves developing a prototype quickly to demonstrate an unclear aspect of system design, and is often aided by CASE tools.

Agile Methodologies

• Agile methodologies have a different approach to design specifications, where design specifications come from code instead of verbal text descriptions.
• Agile methodologies include eXtreme Programming (XP) and Rapid Application Development (RAD).
• XP has four constraints that facilitate simple design: the system must communicate everything, contain no duplicate code, have the fewest possible classes, and have the fewest possible methods.

Electronic Commerce Application

• Finalizing design specifications for electronic commerce applications involves defining required fields for each page identified in the design phase.
• Key features of the human-computer interface may include menu-driven navigation, lightweight graphics, form and data integrity rules, and template-based HTML.

Summary

• This chapter covered the need for system design specifications and how they vary by system development methodology.
• It also covered reading and understanding structure charts, the roles of prototyping and CASE tools, and how design specifications apply to Agile methodologies.
• Additionally, it demonstrated how to declare design specifications for electronic commerce applications.

Understanding data structures and their components, including data elements. Learn how data elements are handled as a unit in a data structure.