Chapter 11 - Describing Process Specifications and Structured Decisions
- Methods Available
- Overview of Process Specification
goals of producing process specificiations:
- to reduce ambiguity of the process
- to obtain a precise description about how a process works.
- to validate the systems design
categories that do not require specs:
- input/output processes
- simple data validation processes
- prewritten code processes
Process Specification Format (Fig. 11.2)
- process # (matches the process ID on the DFD)
- process name (matches the name displayed on the DFD)
- brief discription of what the process accomplishes
- list of data input flow (from DFD and data dictionary)
- list of data output flow (from DFD and data dictionary)
- type of process (batch, online, manual)
- names of subprograms or functions contained within prewritten code
- description of process logic
- reference to structured English, decision table, or decision tree
- unresolved issues, incomplete portions of logic, other concerns.
- Structured English
- Express all logic in terms of sequential, decision (case) or iteration structures
- Captialize keywords
- Indent blocks of statements
- Underline words defined in the data dictionary
- Clarify logic statements (and , or, greater than, greater than or equal to)
- Decision Tables
Conditions and Actions |
Rules |
Conditions |
Condition Alternatives |
Actions |
Action Entries |
- determine the number of conditions that may affect the decision
- determine the number of possible actions that can be taken
- determine the number of condition alternatives for each condition (Y or N)
- Maximum number of columns = # of alternatives ^ number of conditions
- Fill in the condition alternatives
- Insert X's where rules suggest an action
- Combine rules where an alternative doesn't make a difference in the outcome
- Check the table for impossible situations, contradictions, and redundancies
- Rearrage the conditions / actions if necessary
- Decision Trees
- Identify all conditions and actions and their order and timing.
- Begin building the tree from left to right while making sure you are complete in listing all possible alternatives before moving over to the right.
- Choosing a Structured Decision Analysis Technique
- Use structured English when
- There are many repetitious actions.
OR
- Communication to end user is important.
- Use decision tables when
- Complex combinations of conditions, actions, and rules are found.
OR
- You require a method that effectively avoids impossible situations, redundancies, and contradictions.
- Use decision trees when
- The sequence of conditions and actions is critical
OR
- When not every condition is relevant to every action.
- Physical and Logical Process Specifications
Transparencies
Exercises: (due - noon Oct. 29, 1998)
e-mail to summers_wayne@ColumbusState.edu your answers to the following problems: pg. 375: 1,2,3
turn in on Oct. 20th a solution to Group Project # (this may be completed in a small group of 3 to 4 students)
Explore the MRE HyperCase company and e-mail the answers to the question #1 on page 374[This can be done in a group of 2-3]