ISO/IEC/IEEE 31320-2

Description / Abstract: This standard defines the semantics and syntax of IDEF1X. It does so by defining the valid constructs of the language and specifying how they can be combined to form a valid model.

IDEFIX takes the approach that an enterprise manages what it knows about (its knowledge). Such knowledge consists of awareness about enterprise-pertinent actions, facts, and the relationships among them. In order to maximize the utility of this knowledge, it must be codified in a manner that makes its interpretation consistent. Without this guidance, the knowledge is either not understood at all or, worse, misused to draw unsupported or inappropriate conclusions. The guide to the interpretation and use of the enterprise knowledge has three components:

a) A grammar that dictates the kinds of actions, facts, and relationships that the enterprise is interested in recording,

b) Operations that can be performed on/with this knowledge to produce usable information, and

c) Rules about recorded knowledge that help the enterprise weed out conflicting statements and rules that govern the state changes that recorded knowledge can undergo.

For example, the sentence "The chair sings the tree" is grammatically sound in English; there is a subject, a verb, and an object in the sentence. However, the sentence itself is not useful because it states something that is nonsensical. In a natural language, rules must be established that, for instance, indicate that the subject of the sentence must be capable of taking action, if the verb is an action, and of taking the particular action specified by the verb.

Such a guide to the interpretation and use of the enterprise knowledge is, itself, captured as a set of facts. This body of facts about facts, or metaknowledge, in turn needs a guide to its understanding and use. This goal, in a nutshell, is the scope of IDEF1X. As part of its semantics and syntax, IDEF1X establishes just what can be said about the enterprise knowledge and what sorts of conclusions can be drawn from that metaknowledge.

This standard does not treat methodology. A methodology is an ordered process used to produce a repeatable result. An IDEF1X methodology deals with the process of creating a model using the IDEF1X language. While critical to the practitioner, such considerations are beyond the scope of this standard. Rather, the IDEF1X constructs will be presented individually, without regard for their logical sequence of use.

Purpose

This purpose of this standard is to describe the IDEF1X language in an unambiguous manner and thereby meet two important needs. First, those who develop and use IDEF1X models need a common understanding of the modeling constructs and rules. A precise definition of the meaning of the language components allows a model developed by one individual or group to be understood by another. Second, IDEF1X users must be supported in practice by automated tools that record and validate the models. Tool developers need a precise definition of the language so that their products assist users in applying the language correctly and allow exchange of models, at the semantic level, with other tools.

The purpose of IDEF1X as a modeling technique is the same as that of all modeling techniques employed in system analysis and development efforts, that is, to plan, build, or use systems and information systems in particular, it helps to understand the meaning of the concepts involved. Modeling provides a "language" for meanings and is sometimes referred to as closing the semantic gap between the concepts of the enterprise and the capabilities of the computer systems. Figure 1 summarizes the fundamental purpose of a model: to enable accurate and useful communication among users, analysts, and developers as they all reason about the same thing.

There are many uses for models, including process re-engineering, enterprise integration, detailed specification, implementation, and reverse engineering. Each is important.