A typical model consists of an aggregation of submodels. Each submodel is a partial description and is created for a specific purpose; it may be comprised of one or more diagrams. The collection of submodels may employ multiple modeling languages or a single modeling language. The Unified Modeling Language (UML) recognizes a rich collection of modeling diagrams. Use of these diagrams, along with the modeling language constructs, brings about three broad model types commonly used: information models, behavioral models, and structure models (see section 1.1).
Information Modeling
Information models provide a central focus on data and information. An information model is an abstract representation that identifies and defines a set of concepts, properties, relations, and constraints on data entities. The semantic or conceptual information model is often used to provide some formalism and context to the software being modeled as viewed from the problem perspective, without concern for how this model is actually mapped to the implementation of the software. The semantic or conceptual information model is an abstraction and, as such, includes only the concepts, properties, relations, and constraints needed to conceptualize the real-world view of the information. Subsequent transformations of the semantic or conceptual information model lead to the elaboration of logical and then physical data models as implemented in the software.
Behavioral Modeling
Behavioral models identify and define the functions of the software being modeled. Behavioral models generally take three basic forms: state machines, control-flow models, and dataflow models. State machines provide a model of the software as a collection of defined states, events, and transitions. The software transitions from one state to the next by way of a guarded or unguarded triggering event that occurs in the modeled environment. Control-flow models depict how a sequence of events causes processes to be activated or deactivated. Data-flow behavior is typified as a sequence of steps where data moves through processes toward data stores or data sinks.
Structure Modeling
Structure models illustrate the physical or logical composition of software from its various component parts. Structure modeling establishes the defined boundary between the software being implemented or modeled and the environment in which it is to operate. Some common structural constructs used in structure modeling are composition, decomposition, generalization, and specialization of entities; identification of relevant relations and cardinality between entities; and the definition of process or functional interfaces. Structure diagrams provided by the UML for structure modeling include class, component, object, deployment, and packaging diagrams.
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Published on : 30-May-2018
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