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DECISION TABLES

DECISION TABLES. Decision Tables. History Describing decision rules and decision procedures in a tabular form goes back at least to ancient Babylon, where the rules for performing multiplication of cuneiform numerals were baked in clay tablets for students.

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DECISION TABLES

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  1. DECISION TABLES

  2. Decision Tables History Describing decision rules and decision procedures in a tabular form goes back at least to ancient Babylon, where the rules for performing multiplication of cuneiform numerals were baked in clay tablets for students. Tables are a quick and easy way to read, understand and communicate decision rules and to execute a complex procedure. Decision table

  3. Decision Tables History Tabular forms for computer programming date back to the late 1950's and 1960’s when General Electric, the United States Air Force, Siemens and others worked on complex projects. Decision tables were first used for program specifications, leaving it to the programmers to translate the tables into code by hand.

  4. Decision Tables History In the 1960’s and 1970’s decision table software was written for the analysis of decision tables and for code generation from decision tables. Dr. Reinhold Thurner, of the University of Zurich and Sodecon AG, Zurich, created DETAB – a DEcision TABle GeneraTor. At mbp in Dortmund they created VORELLE. Dr. Horst Strunz made contributions to this project and wrote the first textbook on decision tables in Germany. In the 1970’s and 1980’s such systems were used in all major companies. The early decision table programs were written in either mainframe assembly languages or COBOL.

  5. Decision Tables History The Canadian Standards Association issued a formal standard for decision tables in 1970 (DECISION TABLES, CSA Standard Z243.1-1970), which can be obtained through the American National Standards Institute (ANSI) in the United States. In Germany decision tables were introduced as national standard DIN 66241 in 1978.

  6. Decision Tables History During the 1990’th decision tables disappeared in many places. The decision table software was not available on personal computers. And some companies that were pioneers in decision table technology no longer exist – like mbp in Dortmund. In the new century we have new initiatives for the application of decision tables and new decision table software is available like PROLOGA or LogicGem

  7. Decision Tables Basic Elements of a Decision Table Decision table - Wikipedia

  8. Rule Identifiers Name of Table Conditions Actions Decision Tables Supplementary Elements of a Decision Table

  9. Y : YES N: NO # = UNDEFINED = DO NOT CARE X = ACTION TO BE TAKEN = ACTION NOT TO BE TAKEN Decision Tables Limited Entry Decision Tables: If in the columns of rules, only an element of the set {Y, N, -, #; x, -} is allowed, the table is called as Limited Entry decision Table. Y, N, - and # are the indicators for conditions. X and – are the indicators for actions.

  10. Decision Tables Limited Entry Decision Tables: If in the columns of rules, only an element of the set {Y, N, -, #; x, -} is allowed, the table is called as Limited Entry decision Table. !!!!! In a limited entry Decision Table, Max. Number of rules: 2n (n: number of conditions)

  11. Decision Tables Extended entry : Amount ? (<X, =>X and <Y, =>Y) Limited entry : 1. Amount <X ? (Yes, No) 2. Amount =>X and <Y ? (Yes, No)

  12. Decision Tables Crane example – limited entry decision table

  13. Decision Tables Mixed Decision Table

  14. Decision Tables Extended Decision Table

  15. Decision Tables Decision Table of Check Encashment 1

  16. Decision Tables Decision Table of Check Encashment 2

  17. Decision Tables Equivocal Decision Tables

  18. Decision Tables Equivocal Decision Tables with Contradictory rules

  19. OUR TARGET The aim of a decision table by analyzing and documenting decisions is to build a complete and confliction free Tables. Decision Tables Our Target

  20. Decision Tables Combination of Conditions

  21. Decision Tables Combinationof Actions

  22. LOGIC OF DECISION TABELS Exclusive OR Connection of Rules Decision Tables OR - Combination of Rules

  23. Decision Tables ELSE-rule covers the missing condition combinations C1 C2 C3 An example of Else rule’s application

  24. Decision Tables Development of a decision table 2

  25. Decision Tables Development of a decision table 3

  26. Decision Tables Development of a decision table 4

  27. Decision Tables Development of a decision table 5

  28. Decision Tables Decision table

  29. Decision Tables • STEPS OF DERIVING A DECISION TABLE FROM A TEXT • Check and analyze the text (The aim is to understand what are the decision situations) • Mark the conditions • Mark the actions • List the conditions • List the actions • Check opportunities • to group according to similar conditions and actions • build classes • 7. Order list of the conditions according to the cluster • 8. Enter rules according to the clusters • 9. Check • Completeness • Contradictions…

  30. Decision Tables EXAMPLE : • Develop a complete limited entry decision table for the following decision situation: • An airline offers only flights in Germany and Europe.Under special conditions a discount is offered – a discount with respect to the normal airfare. • Rules: • Passengers older than 18 with destinations in Germany are offered a discount at 20%, if the departure is not on a Monday or Friday. If the passengers stay at least 6 days at the destination, an additional discount of 10% is offered. • For destinations outside of Germany passengers are offered a discount of 25%, if the departure is not on a Monday or Friday. • Passengers older than 2 but younger than 18 years are offered a discount of 40% for all destinations. • Children under 2 travel for free.

  31. Decision Tables CONDITIONS AGE: <2 2-18 DESTINATION: In Germany DAY OF THE WEEK: Monday or Friday STAY AT THE DESTINATION: More than six days ACTIONS 100% Discount, 40% Discount 25% Discount 20% Discount 10% Discount 0% Discount

  32. Decision Tables Decision Table of airlines example

  33. Decision Tables Decision Table in PROLOGA

  34. General information of program (title, author, company, description) The program is consisted of 5 conditions, 6 actions, 6 rules and 6 columns. Lists of conditions, actions and rules Decision Tables Decision Table as XML

  35. Decision Tables Conditions as XML

  36. Decision Tables Actions as XML Rules as XML

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