4.13 Elementary Method "Decision Table Technique" (DTAB)

1 Identification/Definition of the Method

/DIN 66241, 1978/ pp. 1-4

2 Brief Characteristic of the Method

Objective and Purpose

The Decision Table Technique (DTAB) is a means to represent decision situations in a clear, unambiguous, and brief manner.

The decision tables used in this connection are composed of a number of decision rules relevant in a certain situation. A decision rule defines an action or a sequence of actions that are to be executed for a certain combination of satisfied conditions.

Means of Representation

A decision table consists of

• the condition part listing the conditions relevant in the decision situation,
• the action part containing a list of all possible actions,
• the condition indicating part containing the combinations of the states possible for the conditions, and
• the action indicating part that can be used to define the corresponding actions to be carried out.
Decision tables can be linked with follow-up decision tables, depending on the complexity of the decision situation to be represented.

Operational Sequence

The application is realized with the following steps:

1. Recording of the initial situation
• The conditions and actions are defined and listed.
• All combinations of condition indicators that are formally possible are specified.
• The action indicators are completed rule by rule.
• The table is checked if unambiguous and complete.
2. Selection of the applying decision rule
If the current condition constellation is known the decision rule applying to this case will be selected.
3. Execution of the actions
With the execution of the action defined in the selected rule the decision process is completed.

3 Limits of the Methods Application

Returns and loops within complex decision processes can be represented, though not in a very clearly set up way. Checking completeness, redundancy, and consistency requires the support of a tool.

4 Specification of the Methods Allocation

No. Activity Description
4.1 SD2.6 - Specification of System Integration On the one hand, applying the decision table technique allows the description of the integration steps required to combine the segments to the system, the SW/HW Units to Segments and the SW Components, SW Modules and the Databases to SW Units. Also described are, e. g., requirements needed for the individual segment integrations and which combinations are possible or necessary.

On the other hand, the integration instructions for all integration steps are described, as e. g.

• organizational requirements
• allocation of roles
• responsibilities
• parts of the development environment and target computer
• assessment environment
• hardware
• available software
The subproduct Integration Plan.Integration Instructions (for System, Segment, SW) is completely covered .
4.2 SD3.3 - Definition of Requirements for the Functionality The conditions and actions of a function are represented in the form of rules and of depending actions.

The subproduct Technical Requirements.Overall Function of Element is covered with regard to the difference between cases in the functions.

5 Interfaces

- not applicable -

6 Literature

/DIN 66241, 1978/ DIN 66241: Entscheidungstabellentechnik für den Informationsaustausch
/Elben, 1973/ Entscheidungstabellentechnik - Logik, Methodik und Programmierung
/Strunz, 1977/ Entscheidungstabellentechnik: Grundlagen und Anwendungsmöglichkeiten bei der Gestaltung rechnergestützter Informationssysteme

 GDPA Online Last Updated 01.Jan.2002 Updated by Webmaster Last Revised 01.Jan.2002 Revised by Webmaster