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| Annex 2 | |||
| 2.2 The complex Method IEM |
IEM - Information Engineering Method
 Contents
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1 Brief Description
IEM (Information Engineering Method) consists of a set of coordinated concepts and methods for the integrated development of commercial software. IEM is predominantly applied for the design of information systems, from the planning to the generation of programs and databases. IEM supports the entire software development process within the scope of a phase concept with the following main phases: strategic information planning, user-level system analysis, technical system design, implementation. IEM requires a development database in which all the results derived from the various methods are counterchecked and consolidated so the development database is only comprised of assessed and consistent information.
The methodical components of IEM are:
- Action Diagrams
Action Diagrams allow the representation of a functional or respectively module structure with successive hierarchical refinement up to the level of the program logic.
- Decomposition Diagrams
Decomposition Diagrams can be used for the hierarchical decomposition of business functions, processes, procedures, and program modules.
- Dependency Diagrams
Dependency Diagrams are used to represent the dependencies of functions, processes, and procedures.
- Data Flow Diagrams
Data Flow Diagrams are used for the data flow modeling.
- Data Analysis and Data Structure Diagrams
Data Analysis and Data Structure Diagrams are used for the bottom-up generation of data structures.
- Entity-Relationship Diagrams
By utilizing the Entity-Relationship Diagrams it is possible to generate E/R models with binary relation types between entity types.
- Data Navigation Diagrams
Data Navigation Diagrams can be used to represent the order and mode of the data accesses to the entity types of an E/R model.
- Decision Trees and Decision Tables
Decision Trees and Decision Tables correspond to the requirements of the decision table technique (DTAB) of the Methods Standard.
- State Transition Diagrams
With the help of the State Transition Diagrams it is possible to model the states of processes, in particular the states of real-time processes.
- Dialog Design Diagrams
Dialog Design Diagrams are used for the design and representation of user dialogs.
- Entity LifeCycles
Entity LifeCycles can be used to represent the life cycle of entity types via State Transition Diagrams.
- Physical Database Design
Physical Database Design is used for the generation of physical data structures with logical DB modeling as interim step.
- Normalization
Normalization is used for the normalization of entity types. IEM was designed by J. Martin, adopted by various consulting companies, and slightly modified (Ernst & Young, J. Martin Corporation, Texas Instruments etc.). The present comparison refers to the IEM representation by J. Martin the way it is described in the following J. Martin books about Information Engineering: /Martin, 1987/, /Martin, 1989/, /Martin, 1990a/ and /Martin, 1990b/.
2 Tabular Comparison
The following table compares the basic methods of the GD 251 with the methodical components of IEM. In the case where there is no entry in the right column of the table, IEM has no corresponding component. Otherwise an entry refers to the corresponding part. In the IEM literature section 3 of the comparison contains explanations for the entries. Entries identified with (*) refer to basic methods completely covered by IEM. These are not further described in section 3.
3 Specification of the Allocation
| Method | Corresponding Component in IEM | Explanation |
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FNET Function Net Modeling | Dependency Diagrams /Martin, 1990a/ chap. 14 | The dependencies of functions are represented in IEM by means of "Process Dependency Diagrams". Apart from the dependencies of functions it is also possible to model how often a dependent function is to be executed and if the courses of functions are to exclude each other. It is also possible to model events that initialize certain functions. The functions of Process Dependency Diagrams can be linked with the data from the corresponding E/R model. The modeling of processes can be checked for completeness via Data Conversation Analysis, Data Model Completeness Analysis, Process Model Completeness Check. |
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LOGM Logical DB Modeling | DB Modeling in IEM is represented within the scope of the detailed database design (/Martin, 1990b/ chap. 15, pp. 325-341). | In the IEM description, logical data modeling is handled together with the physical database design (chap. 15: "Physical Database Design" in /Martin, 1990b/). It lists the influence factors for the design of a DBMS-oriented data structure together with those required for a physical database design. A clear line between logical database modeling and physical database design is only drawn in the IEM modifications (e. g. by Ernst & Young within the scope of the product IEW/ADW). IEM does not include any rule systems used to transform E/R models into actual commercially available database systems. Such rule systems are only included in the modifications or upgrades of the method by software producers. |
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STRD Structured Design | In IEM, Structured Design is handled within the scope of modeling with action diagrams where Structure Charts are only taken into consideration thus far as they can be represented as special cases of Action Diagrams (/Martin, 1990b/ Appendix II). | Modifications or upgrades of IEM with regard to STRD (e. g. by Ernst & Young) use classical Structure Charts according to /Yourdon-Constantine, 1979/ or else expand the Action Diagrams accordingly (e. g. James Martin Corporation with "Procedure Logic Design"). |
4 Literature
/Martin, 1987/ Diagramming Standards for Analysts & Programmers/Martin, 1989/ Information Engineering, Book I
/Martin, 1990a/ Information Engineering, Book II
/Martin, 1990b/ Information Engineering, Book III
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