once the table is completed, rules which result in the same actions can be joined together and represented by dashes, that is, 'it does not matter'. The result of this is a consolidated decision table. Figure 12.12 illustrates an example decision table before and after the consolidation process. In the decision table represented in figure 12.12(b), Rules 3 and 4 of the decision table seen in figure 12.12(a) have been merged into a consolidated rule 2, expressing a 'doesn't' matter' condition. This is because the same processing needs to be executed whether or not condition 2 is'yes' or 'no'.in system analysis, there are likely to be requirements to specify actions where there are a large number of conditions. A set of decision tables is appropriate here. The first will have actions such as 'go to decision table 2' or 'go to decision table 3'. Each of these may themselves be reduced to a further level of decision tables. The technique therefore lends itself to functional decomposition.Sometimes the values of conditions are not restricted to 'yes' or 'no', as defined in the limited entry tables described. There can be more than two possible entries, and extended entry tables are appropriate in this case. For example, the credit allowable to a customer could vary according to whether the customer has been dealing with the firm for 'up to 5 years'.'over 5 and up to 10 years', 'over 10 and up to 15 years', and so on. The rule for obtaining the right number of combinations will need to be modified. If Condition 1 has two possibilities and Condition 2 five possibilities, then the number of columns will be 2 x 5, that is, 10 columns.
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