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 modeling techniques. They cover a range of uses from function modeling to information, simulation, object-oriented analysis and design and knowledge acquisition. Specifically, the initial (and most-widely recognized) languages are IDEF0, which is a functional modeling language building on SADT, and IDEF1, which addresses information models; an adaptation of IDEF1, called IDEF1X, was subsequently created to address database design issues. The IDEF languages were developed under funding from U.S. Air Force and, as such, are in the public domain.
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[edit] History
IDEF was a product of the Integrated Computer-Aided Manufacturing (ICAM) initiative of the United States Air Force. "IDEF" initially stood for "ICAM DEFinition" language; the IEEE standards recast IDEF as "Integration DEFinition."
The specific projects that produced IDEF were ICAM project priorities 111 and 112 (later renumber 1102). The subsequent Integrated Information Support System (IISS) project priorities 6201, 6202, and 6203 were an effort to create an information processing environment that could be run in heterogeneous physical computing environments. Further development of IDEF occurred under those projects as a result of experience gained applying the new modeling techniques. The intent of the IISS efforts 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.
[edit] Information Modeling
At the time of the ICAM 1102 effort there were numerous, mostly incompatible, methods for storing computer data — Sequential (VSAM), Hierarchical (IMS), Network (Cincom's TOTAL and CODASYL, and Cullinet's IDMS). The relational data model was just emerging as a promising way of thinking about structuring data for easy, efficient, and accurate access. Relational Database Management Systems had not yet emerged as a general standard for data management.
The ICAM program office deemed it valuable to create a "neutral" way of describing the data content of large-scale systems. The emerging academic literature suggested that methods were needed to process data independently of the way it was physically stored. Thus the IDEF1 language was created to allow a neutral description of data structures, that could be equally applied regardless of the storage method or file access method.
IDEF1 was developed under ICAM program priority 1102 by Dr. Robert R. Brown of the Hughes Aircraft Company, under contract to SofTech, Inc. Dr. Brown had previously been responsible for the development of IMS while working at Rockwell International (Rockwell chose not to pursue IMS as a marketable product; International Business Machines (IBM), which had served as a support contractor during development, subsequently took over the product and was successful in further developing it for market.) Dr. Brown credits his Hughes colleague Mr. Timothy Ramey as the inventor of IDEF1 as a viable formalism for modeling information structures. The two Hughes researchers built on ideas from and interactions with many luminaries in the field at the time. In particular, IDEF1 draws on the following techniques:
- the Evolving Natural Language Information Model (ENALIM) technique of Dr. G. M. Nijssen (Control Data Corporation) — this technique is now more widely known as NIAM or the Object-Role Model ORM;
- the network data structures technique, popularly called the CODASYL approach, of Dr. C. W. Bachman (Honeywell Information Systems);
- the hierarchical data management technique, implemented in IBM's IMS data management system, developed by Dr. R. R. Brown (Rockwell International);
- the relational approach to data of Dr. E. F. Codd (IBM);
- The Entity-Relationship Approach (E-R) of Dr. P. P-S. Chen (UCLA).
The effort to develop IDEF1 resulted in both a new method for information modeling and an example of its use in the form of a "reference information model of manufacturing." This latter artifact was developed by D. S. Coleman of the Dan Appleton Company (DACOM) acting as a sub-contractor to Hughes and under the direction of Mr. Ramey. Personnel at DACOM became quite expert at IDEF1 modeling and subsequently produced a training course and accompanying materials for the IDEF1 modeling technique.
[edit] Database Modeling
Experience with IDEF1 revealed that the translation of information requirements into database designs was more difficult than had originally be anticipated. The most beneficial value of the IDEF1 information modeling technique was its ability to represent data independent of how those data were to be stored and used. It provided data modelers and data analysts with a way to represent data requirements during the requirements-gathering process. This allowed designers to face the decision of which DBMS to use under various circumstances after the nature of the data requirements was understood. The result was reduction of the "misfit" of data requirements to the capabilities, and limitations, of the DBMS. The translation from IDEF1 models to database designs proved to be difficult, however.
IDEF1X was a result of the ICAM IISS-6201 project and was further extended by the IISS-6202 project. The sub-contractor making the most contribution to the content of IDEF1X was DACOM. Principal contractors included Boeing and McDonnell Douglas Corporations.
To satisfy the database modeling enhancement requirements that were identified in the IISS-6202 project, DACOM obtained a license to the Logical Database Design Technique (LDDT) and its supporting software (ADAM), which had been independently developed in 1982 by Robert G. Brown of The Database Design Group. LDDT combined elements of the relational data model, the E-R model, and data generalization in a way specifically intended to support database design. Most of these features were already present in the IDEF1 language, making the extension to IDEF1X quite natural. Mary E. Loomis of DACOM wrote a concise summary of the syntax and semantics of a substantial subset of LDDT, which DACOM adapted to be compatible with IDEF1 and supplied to the ICAM program as IDEF1X. (IEEE 1998, p. iii) (Bruce 1992, p. xii)
Because the IDEF languages were produced under government funding, the techniques are in the public domain. 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 JDBC are now achieving the goals of ubiquity and versatility across computing environments which was first demonstrated by IISS.
[edit] IDEF Methods
As of 1995 methods 5 through 14 have not been pursued in depth.[1]
- IDEF0
- Function Modeling [2]
- IDEF1
- Information Modeling [3]
- IDEF1X
- Data Modeling [4]
- IDEF2
- Simulation Model Design
- IDEF3
- Process Description Capture [5]
- IDEF4
- Object-Oriented Design [6]
- IDEF5
- Ontology Description Capture [7]
- IDEF6
- Design Rationale Capture [8]
- IDEF7
- Information System Auditing
- IDEF8
- User Interface Modeling
- IDEF9
- Scenario-Driven IS Design
- IDEF10
- Implementation Architecture Modeling
- IDEF11
- Information Artifact Modeling
- IDEF12
- Organization Modeling
- IDEF13
- Three Schema Mapping Design
- IDEF14
- Network Design
[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.
- Bruce, Thomas A. (1992), Designing Quality Databases with IDEF1X Information Models, ISBN 0932633188
[edit] See also
[edit] External links
- Integration Definition for Information Modeling (IDEFIX) -- 93 Dec 21 - The now-obsolete FIPS 184 standard for IDEF1X described the 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 permitted the construction of semantic data models which supported the management of data as a resource, the integration of information systems, and the building of computer databases. This standard was superseded by IEEE 1320.2-1998, which is now the national standard for IDEF1X.
- Integrated DEFinition Methods
- Data Modeling
