System Analysis Mr Ahmad AlGhoul Learning Objectives n

System Analysis - Mr. Ahmad Al-Ghoul

Learning Objectives n n Discuss and understand the decision tables types Use decision tables to analyze and describe processes Avicenna System Analysis and Design System Analysis 2

Process Description Tools n Decision Tables Shows a logical structure, with all possible combinations of conditions and resulting actions n It is important to consider every possible outcome to ensure that you have overlooked nothing n Can have more than two possible outcomes n Often are the best way to describe a complex set of conditions n Avicenna System Analysis and Design System Analysis 3

Process Description Tools Decision Tables n Decision tables are used to: n n n Describe the conditions. Identify possible decision alternatives. Indicate actions should be performed. Describe actions. Standard procedure for creating decision tables n n n Avicenna Name the condition and values Name all possible actions that can occur List all rules Define the actions for each rule Simplify the table System Analysis and Design System Analysis 4

Process Description Tools n Decision Tables n Consists of four quadrants Conditions Rules A list of all possible conditions that can arise within the process Action Entries A list of all possible actions that occur within the process Avicenna contains selectors which identify different combinations of the possible conditions indicators which select the actions to be performed System Analysis and Design System Analysis 5

Process Description Tools n Decision Tables n n Avicenna The number of conditions and rules are related, each condition has two possible values, the number of rules doubles each time you add a condition. Number of rules = 2^N where N represents the number of condition Some rules can duplicates, however, the table can be simplifies If you have rules with three conditions, one or two of them may control the outcome, other conditions don’t matter. You can indicate that with ( - ) and that’s mean you don’t need to examine them. System Analysis and Design System Analysis 6

Process Description Tools n In the example, the credit manager can waive the credit status requirement in certain situations. To ensure that all possibilities are covered, notice that the first condition provides an equal number of Ys and Ns, the secondition alternates Y and N pairs, and the third condition alternates single Ys and Ns. [1] Avicenna System Analysis and Design System Analysis 7

Process Description Tools n Decision Tables n Limited Entry Decision Table n Mixed Entry Decision Table n Extended Entry Decision Table Avicenna System Analysis and Design System Analysis 8

Process Description Tools n Limited Entry Decision Table n Avicenna Contains only the binary selectors Y & N and the ( - ) in the rules quadrant. In the action entries, it contains only the action selector symbol X. System Analysis and Design System Analysis 9

Process Description Tools n Mixed Entry Decision Table n Contains only the binary selectors Y & N and the ( - ) in the rules quadrant. In the action entries quadrant, indicators other than X appear. Salaried Employee Hours Worked > 40 Pay Avicenna 1 2 3 N Y N N Y - Overtime Regular rate System Analysis and Design System Analysis Regular rate 10

Process Description Tools n Extended Entry Decision Table n Selectors in the rules quadrant are no longer simply binary (y or N) they may take specific values or ranges of values. Approved Credit Quantity Ordered Discount (%) Accept Order Reject Order Avicenna 1 2 3 4 N - Y 0 -24 Y 25 -55 Y 56 -99 0% X 5% X 10% X X System Analysis and Design System Analysis 11

Process Description Tools Decision Tables n Advantages of Decision Tables Easily understood n Alternatives are shown side by side n Cause & effect relationship is shown, thus permitting easier user validation n Possible to check that all combinations of conditions have been considered n Avicenna System Analysis and Design System Analysis 12

Sequence Summary n n n Decision tables provide anther way to examine, describe, and document decisions Four quadrants are used to describe the conditions, identify possible decision alternatives, indicate which actions should be performed, and describe the actions Three types of decision tables are Limited Entry Decision Table n Mixed Entry Decision Table n Extended Entry Decision Table n Avicenna System Analysis and Design System Analysis 13

Sequence Summary n In this Sequence we have n Defined and explained decision tables n Described the decision tables quadrants which used to describe the conditions, identify possible decision alternatives, indicate which actions should be performed, and describe the actions n Explained the three types of decision tables Limited Entry Decision Table n Mixed Entry Decision Table n Extended Entry Decision Table n Avicenna System Analysis and Design System Analysis 14

Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt , Publisher: SHELLY CASHMAN SEWIES. [2] system analysis and design, sixth edition Authors: Kenneth E. Kendall and Julie E. Kendall Publisher: Prentice Hall [3] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich Publisher: prentice hall [4] System Analysis and Design, 3 rd Edition Authors: Dennis, Wixom, & Roth Publisher: John Wiley & sons Avicenna System Analysis and Design System Analysis 15