Decision Table

Decision Table

A decision table is a graphical method for explaining the logic of making decision in tabular format.

It is a set of conditions + set of actions and different combinations of decisions.

“It is a matrix representation of logic of decisions which specify the possible conditions for decision and resulting actions.”

The decision table is divided into two parts:

1.    Condition

2.    Action

1.    Condition:

The condition part specifies all conditions that are applied to the inputted data. It is also divided into two parts à

                                                       i.            Condition Stub:-

It describes the conditions that exist in the program logic.

                                                     ii.            Condition Entry:-

It provides answers to questions asked in the condition asked in the condition term.

2.    Action:

The action part is subdivided into two parts à

                                                       i.            Action Stub:-

It describes the action to be taken to meet each condition.

                                                     ii.            Action Entry:-

It describes the appropriate action resulting from the answer to the condition in condition entry.

Format:

Table Heading

Decision Rule

Condition Stub

Condition Entry

Action Stub

Action Entry

Advantages of Decision Table

1.    It provides compact representation of decision making process.

2.    It is easier to understand particular path.

3.    It can be changed according to situation.

4.    These are best suited for calculating discounts, commissions or inventory control procedures.

5.    The structure of decision table promotes a logically complete and consistent problem definition.

Disadvantages of Decision Table

1.    It cannot express the complete sequence of operations to solve a problem therefore it may be difficult for the programmer to translate decision table into program.

2.    If there are too many alternatives, it is difficult to list in decision table.

3.    It does not show the flow of logic for the solution to a given problem.