Model   A model is a cohesive and complete representation of a system from a particular perspective. The perspectives are not predefined but there are a number of commonly used perspectives, such as use case model, analysis model, design model which are detailed in the UML Profile for Software Development Processes. Each model can form part of a model hierarchy, whose root is the topLevel package representing the entire entity being modeled (usually a system), and whose individual nodes are the models themselves.

Explanation

A model is one of a number of ways of organizing a modeling endeavor. It is cohesive and complete in the sense that it is a higher order concept than a diagram or view, which both have the characteristic of a perspective, but are often not complete and cohesive. A model is a collection of model elements. Together the set of models and the model elements they contain forms a well ordered hierarchy. The subsystem hierarchy, which can also be used to organize or partition a modeling effort, is often orthogonal to the model hierarchy.

Important Points

A model is a stereotype of package and has all of the usual package properties and behavior.

A model is a type of package that presents a view of the physical system. Models can be nested and form hierarchies that help to break the system up into a number of manageable parts or views. The models present a view of the system from a particular viewpoint that is usually of interest to one or more parties. Some confusion arises here because of the varied way that the terms subsystem, model, view and viewpoint are used.

Related Entries

Package  Graphically Similar,  Confused with A package is related to a model in the sense that a model is a stereotype of a package, thus the model has all of the fundamental properties of the package. The essential nature of the package, being a grouping of model elements, is the core of the model element.

Subsystem  Graphically Similar,  Confused with A subsystem, in its most vanilla form, has the same representation as the model - the "folder" icon. Both are used to provide a view or segment an entire system into more manageable parts. The subsystem divides the physical system up on a behavioral axis, the model is more generic and the purpose of the model specifies the axis.