IDEF
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The family of ICAM Definition Languages, short IDEF, were initiated in the 1970s and finished being developed in the 1980s. These "definition languages" have become standard modelling techniques. They cover a range of uses from function modelling to information, simulation, object-oriented analysis and design and knowledge acquisition. Specifically, IDEF0 is a functional modelling language building on SADT, and IDEF1X addresses information models. IDEF1X was created by the U.S. Air Force based on ERDs.
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[edit] History
IDEF was a product of the Integrated Computer-Aided Manufacturing (ICAM) initiative of the United States Air Force. Dennis E. Wisnosky is recognized as a creator of the Integrated Definition (IDEFs) language, the standard for modeling and analysis in management and business improvement efforts. "IDEF" stands for ICAM DEFinition language.
The specific projects that produced IDEF were the Integrated Information Support System (IISS) project priorities 6201, 6202, and 6203. IISS was an effort to create an information processing environment that could be run in heterogeneous physical computing environments. The intent was to create 'generic subsystems' which could be used by a large number of collaborating enterprises, such as U.S. Defense contractors and the armed forces of friendly nations.
At the time, there were numerous, mostly incompatible, methods for storing computer data — Sequential (VSAM), Hierarchical (IMS), Network (Cincom's TOTAL and CODASYL, and Cullinet's IDMS). Relational Database Management Systems had not yet emerged as a general standard for data management.
The ICAM project office deemed it valuable to create a "neutral" way of describing implemented physical data structures so that a way could be found to process data independently of the way it was physically stored. Thus the IDEF1 language was created to allow a neutral description of existing physical data structures that could be equally applied regardless of the storage method or file access method.
IDEF1 was the result of the IISS-6201 project, and was further extended into IDEF1X by the IISS-6202 project.
The sub-contractor making the most contribution to the content of IDEF1 (and IDEF1X) was DACOM, the Dan Appleton Company. Principle contractors included Boeing and McDonnell Douglas Corporations.
The most beneficial value of the IDEF1 data modeling technique was its ability to represent data structures independent of how they are to be stored. So, even though IDEF1 started its existence as a way to model physical data structures in a neutral way, it quickly became adopted by data modelers and data analysts as a way to represent data structures during requirements gathering sessions. This allowed the decision of which DBMS to use after the nature of the data structures to be implemented was known, with the potential benefit of reducing the "misfit" of data structure requirements to the capabilities, and limitations, of the DBMS.
As IDEF was produced by government funds, the technique is in the public domain. Therefore many of the earliest CASE tools, such as ERwin, utilized IDEF1X as their representation technique for data modeling.
The IISS projects actually produced working prototypes of an information processing environment that would run in heterogeneous computing environments. Current advancements in such techniques as Java and ODBC are now achieving the goals of ubiquity and versatility across computing environments which was first demonstrated by IISS.
[edit] References
- IEEE Std 1320.1-1998. IEEE Standard for Functional Modeling Language—Syntax and Semantics for IDEF0. New York: IEEE, 1998.
- IEEE Std 1320.2-1998. IEEE Standard for Conceptual Modeling Language Syntax and Semantics for IDEF1X. New York: IEEE, 1998.
[edit] See also
[edit] External links
- Integration Definition for Information Modeling (IDEFIX) -- 93 Dec 21 - Describes the IDEF1X modeling language (semantics and syntax), and associated rules and techniques, for developing a logical model of data. IDEF1X is used to produce a graphical information model which represents the structure and semantics of information within an environment or system. Use of this standard permits the construction of semantic data models which may serve to support the management of data as a resource, the integration of information systems, and the building of computer databases.
- Integrated DEFinition Methods
- Data Modeling
