IPT HSC 1.5) Designing Solutions
- 2. • Designing a solution is the transformation of the specifications into appropriate hardware, software and information processes. • It involves: • purchasing hardware • writing or purchasing software • specifying information processes • Participant development occurs when people within the information system develop the solution.
- 3. • Participant development became a solution because IT personnel were often unable to provide immediate service. • The stages of the system development cycle are affected by participant development in the following way: • Understanding the problem—participant identifies the problem. Information system personnel might be used to advise the participant on possible tools to solve the problem.
- 4. • Making decisions—participant chooses an appropriate solution. • Designing solutions—participant develops the solution, often using guided processes found in application packages. The participant may require some training
- 5. • Implementation—participant begins using the system. This stage is often easier to accomplish with participant development than with a system developed by information system personnel as the participant is familiar with the application and does not require further training. • Testing, evaluating and maintaining— participant is totally responsible for the maintenance and testing of the solution and determining if any changes need to be made to the solution.
- 6. • Advantages: • Participant development is more responsive to participant needs • Potential to save money • less need for IT staff • less time wasted on communication between participants and IT specialists
- 7. • Disadvantages: • Participants are NOT hardware experts • Different participants within an organisation could choose different applications • Increased costs in terms or purchasing and training • Increased access to data leads to greater security problems
- 8. • Design tools assist in the development of a new system. • They include: • context diagrams • data flow diagrams • system flowcharts • decision trees • decision tables • data dictionaries
- 9. • Context diagrams are graphical methods of representing systems by using only a single process together with inputs and outputs. • The input and output sources are also called external entities. • The external entities are linked to the single process through data flow arrows. • Data flow diagrams are graphical methods of representing a system that use a number of processes together with inputs, outputs and storage.
- 10. • DFD’s focus on the flows of data between information processes in a system. • They show where data is: • collected • organised • analysed • stored • processed • transmitted • displayed
- 11. • There are four main symbols” • process • data flow • data store • external entity • To draw a DFD, start with the processes and use data flows to link them to data stores and entities. • The limitation of context diagrams and DFD’s is that, while they identify basic structures, they do not show sequences of operations or decisions that are required.
- 12. • Many information processes that occur are determined by various decisions. • Two tools used to display and analyse decisions are decision trees and decision tables. • A decision tree is a diagrammatic way of representing all possible combinations of decisions and their resultant actions. • A decision table is a table that represents all possible conditions and actions. • The table is divided vertically into conditions and actions, and horizontally into rules.
- 13. • A data dictionary describes the data within a system. • A data dictionary describes each field in a database. • It clarifies characteristics such as: • field name • field size • data type • description • example
- 14. • A system flowchart is a graphical means of representing both the flow of data and the logic of a system. • It documents such things as: • the sequence • the processes • the selection rules and actions • the hardware used