Information System Modeling Method Weekly Dollar (this paper reproduced from Software Engineering Expert Network www.21cmm.com, does not mean GIGIX view) Large information systems are usually very complicated, it is difficult to analyze it directly, and people often use models to design and analyze the system. The model is an abstract representation of certain things in the real world. Abstract meaning is the essential characteristics of the extraction, ignore other secondary factors of things. Therefore, the model reflects the prototype of things and does not equal this prototype. The model is a common means of understanding, analyzing, developing or transforming the prototype. For example, the model is often made in front of the building, so that people can make people have a very clear sense of sensibility to future buildings. Obviously, the building model can also be used to improve the design of the building. In the information system, the model is an indispensable tool in the development process. Information systems include data processing, transaction management, and decision support. In essence, the information system can be seen from a series of ordered models, these ordered models are usually: functional model, information model, data model, control model, and decision model, so-called or order means that the models are respectively Different development levels are established in different developmental stages of the system. Information Modeling Method Introduction Model The expression of the model can be a mathematical formula, a reduced physical device, a chart text description, or a dedicated formal language. There are two ideas established by the model: from top down, gradually refine and bottom up, integrated. The purpose of the model is the purpose of model research, knowledge is the knowledge and model constructive knowledge of the real system, and data refers to the original information of the system, which constitutes an input to the modeling process. Model constructs are the application of specific modeling techniques. The trusted analysis refers to whether the model has been established to meet the system objectives. The expression of the information system model is different from the ordinary system model. Describe the most common way to describe the information system model is to describe the description and illustration. The formal description method is very accurate, rigorous, easy to implement after the system, but it is difficult to master and understand, the model readability is poor, often only the professionals will be used, so it is difficult to promote. The illustration method is intuitive, natural, easy to describe the hierarchical structure, functionality of the system, and easy to learn, usually there is also tool software support, thus become the main description tool for the information system, but this method is not enough. The modeling method of the information system can be divided into: a process-oriented modeling, the modeling of data, the modeling of information, and the modeling of decision-making and object-oriented modeling. The way to model the process is to treat the process as the basic part of the system model, and the data is generated as the process. The most influential process-oriented design method is your YOURDON design. The data-oriented modeling method regards the input output of the model is most important, so the data structure is first defined, and the process module is derived from the data structure, that is, the function follows the data. The most affected data-oriented design method is Jackson design. The difference between the mode-oriented modeling method and the data modeling method is the difference between information and data. Information and data are the most basic terms in the information system. The data refers to the fact that the facts described is the value of the objective entity attribute, and the information is a set of data that constitutes a certain meaning. The information modeling method is started from the logical data model of the entire system, and all basic data entities and their interrelationships in the system are explained through a global information demand view, and then, the entire model is gradually constructed, and the information model recording system is gradually constructed on this basis. The information required for operation, such as: person, location, things, ideas, etc., to analyze the graphical representation of the current system to provide information. The purpose of data modeling is to design and implement database structures that meet system information requirements, that is, data modeling support system design. The decision support system consists of database, model library, and respective management systems. The problem that the decision support system model needs to reflect is the system's decision-making principles and mechanisms, and the system's organization and personnel configuration. Through the modeling of decision-making systems, companies' leaders can have a detailed understanding of the company, thus discovering problems.
If the organizational structure is bloated, the task is unclear, the power scope is unreasonable, etc., according to the corresponding reform. The compared mature decision support system modeling method has Petri Nets and GRAI. Object-oriented analysis method is to use the object-oriented information modeling concept, such as entities, relationships, attributes, etc., simultaneously construct a method of simulating a reality system using packaging, inheritance, and polymorphism. The basic point of the traditional structured design method is a process, and the system is decomposed into several processes. The object-oriented method is to use the viewpoint of constructor. During the development of the system, the common goal of each step is to build a model of a problem domain. In object-oriented design, the initial element is an object, then the object with common features is summarized into a class, an organizational class level relationship, and constructing a library. When applying, select the corresponding class in the class library. The Idef Method's Introduction The meaning of IDEF is Integrated Computer-aidedmanuFacturing, ICAM, DEFINITION. The initial IDEF method was established in the US Air Force ICAM project, initially developed three methods: function modeling (IDEF0), information modeling (IDEF1), dynamic modeling (IDEF2), later, with the successful development of the information system, The following IDEF methods have also been developed: data modeling (IDEF1X), process description acquisition method (IDEF3), object-oriented design (Idef4), use C language OO design method (IDEF4C ), entity description Get method (IDEF5), design theory (Idef6), human-system interaction design method (IDEF8), business constraint discovery method (IDEF9), network design method (IDEF14), etc. According to the purpose, the IDEF method can be divided into two categories: the role of the first class IDEF method is to communicate information exchange between system integration personnel. Main there are: IDEF0, IDEF1, IDEF3, IDEF5. The IDEF0 describes the system function by classifying the relationship between the functional decomposition, such as input, output, control, and mechanism classification). IDEF1 is used to describe important information in the process of operation. The IDEF3 supports the structured description of the system user view. IDEF5 is used to collect truth and acquire knowledge. The focus of the second class IDEF method is the design part of the system development. There are currently two IDEF design methods: IDEF1X and IDEF4. IDEF1X can assist in the design of the semantic data model. IDEF4 can generate high quality design products needed for object-oriented implementation methods. Next, several major IDEF methods will be described below. The role of the IDEF1 information modeling method IDEF1 method is to analyze and communicate the information resources of the system in the demand analysis. IDEF1 is usually used: (1) Determine what information is currently managed in the organization, (2) What is the problem found during the demand analysis, (3) specified in the TO-BE implementation Which information needs to be managed. From the perspective of IDEF1, it is not only the ingredients of the automation system, but also non-automated components, such as personnel, file cabinets, telephones, etc. Unlike the database design method, IDEF1 is a method for analyzing the following issues: the collection, storage and management of enterprise information; the management rules of information; the logical relationship between the information within the enterprise; the lack of good information management caused.
IDEF1 uses a simple graphical convention to express complex rules set. These rules help the modeling (1) real world objects, (2) The physical or abstract link between the real world object, (3) The information management of the real world object, (4) is used to represent information Demand, application and management data structure. One of the objectives of IDEF1 is to provide a structured, procedure for information analysis. IDEF1 can reduce incompleteness, inaccurate, inconsistencies, and inaccuracicity during modeling. IDEF1 is an effective way to describe the needs of enterprise information. Idef1 modeling has laid the database design basis, which gives the information structure definition, providing a description of the demand for basic information requirements. IDEF1 uses procedures, structured technologies to find out the information and business rules used by an organization. IDEF1 requires information users to participate actively, and users should consider how to use and manage information. Finally, the information model is useful in the entire life cycle of the enterprise. The IDEF3 process description method IDEF3 provides a mechanism for the collection and recording process. The IDEF3 records the priority and causal relationships between state and events in natural ways, which provides a structured approach to expressing knowledge of how to work with a system, process or organization. IDEF3 can: record raw data generated during the research process; determine the role of information resources in the main business process of enterprises; record decision-making processes, especially product definition data for manufacturing, engineering, and repairs; management data configuration and Change the control policy definition; system design and analysis; provide analog model. IDEF3 describes the behavior of existing systems or suggests systems. As a tool description system intuitive knowledge, IDEF3 is structured. The IDEF3 also records all time-based information, including priority and causal relationships related to the enterprise processing. The result of IDEF3 description is to provide a structured knowledge base for analysis and design models. Different languages (such as SIMAN, SLAM, GPSS, WITNESS) are different from the configuration predictive data model, and IDEF3 constructs a structured description. These descriptions get a view of what is actually operational or what will be done, while providing different users of the system. IDEF3 has two descriptions: process flow and object status transformation network. The Idef3 process flow description process and the relationship between the process, describes the knowledge of "how to do", as described in the manufacturing process. The relationship between these processes is generated throughout the business process, and the purpose of the description is to explain how things operate. IDEF4 Object-Oriented Design Method The IDEF4 method developed under the US Air Force Armstrong Laboratory advocated can be applied to use object-oriented technology applications. IDEF4 is developed by a professional object-oriented designer and programmer. The most important reason for choosing the IDEF4 method is that it regards object-oriented design is part of a large system development frame, rather than object-oriented design and analysis. Phase isolated. IDEF4 emphasizes graphical syntax in object-oriented design, using graphical graphical syntax and illustration helps to concentrate and communicate important design events. IDEF4 has obvious differences from other object design methods, the most important thing is that it supports the "LeastCommitment" policy to support design assessments in class inheritance, object composition, functional decomposition, and polymorphism. IDEF4 divides object-oriented design activities into discrete, manageable bulk. Each sub-activity is supported by a graphical graphical graphical synthesis of design decisions. The IDEF4 method is easy to make designers balance between design and inheritance, class composition, functional decomposition and polymorphism. IDEF4 is a graphical syntax that provides a consistent framework for the use and development of object-oriented design, and this design is ultimately described by the type unchanged data list and method set. An IDEF4 model consists of two sub-models: class subdranes and method subdranes.
