The logical model

The logical model (or aspect) is an intermediate aspect used to establish major information system structuring decisions independently of technical solutions. It is used to define the structure of both the existing and the future information system at the logical level.

Icon	Name	Definition
Service components
	Process component or process component instance	Supports a complete business process (orchestration role).
	Entity component or Entity component instance	Logical representation of an autonomous business concept.
	Utility component or utility component instance	Provider of infrastructure or transveral services.
	Public component or Public component instance	Provider of public services.
	Function component or Function component instance	Implementation of dialog and interface with the user.
	Presentation component or Presentation component instance	Implementation of dialog and interface with the user.
	"Database" component or component instance	Represents a shared data repository. Used for existing application where service components are not divided up.
System and system federation
	System federation or system federation instance	Representation of systems or sub-systems, of their constitution in sub-systems/components and of their assembly.
	Entreprise Component	Federation representing the organization itself. This is used to provide a root for the assembly of components, applications and system federations.
	Application , Application instance	Federation of a set of components competing to provide services dedicated to a business line or a specific use of the system.
Services, ports, exchange data, etc
	Message	Massage type represent the structure of flows exchanged through service operations.
	Message Part	Part of a Message
	Service, Service operation	Functionality provided by the information system and made public, available and "invokable" by an interface (contract) so as to be mutualized or orchestrated.
	Port : Provided service	Access point to a service provided by a component.
	Port : Required service	Access point to a service provided by a component.
Structuring
	Package, Implementation Package, datamodel Package	These packages breakdown components or systems. The implementation package is used to express the implementation of a component in UML. The Package structures the elements of the logical model (typically interfaces or messages) inside components. Data models are limited to the static model to model data schemas (in general inside Systems).
	Logical architecture unit	Very earliest structuring unit. Used to structure through functional domains, for example. Can be used to represent zones in urbanization.
	Layer	Structures service components according to their nature and degree of stability. Predefined layers are proposed.
	External actor	See the business organization model.
	Internal actor	See the business organization model.
	Authorization	Link defining the right of a given actor to use such and such a service.
	Information flow	See the business organization model.
	Dependency	Link defining a dependency or access between elements.
	Traceability	See the business organization model.

Logical model diagrams

There are seven types of logical model diagram:

· Overview diagrams

· Logical architecture diagrams

· Habilitation diagrams

· Traceability diagrams

· Use case diagrams

· Message diagrams

Overview diagrams

A general logical architecture diagram presents component types and their interfaces. This type of diagram is created using the icon.

Example Overview diagram

Logical Architecture diagrams

A detailed logical architecture diagram presents the way in which components are assembled in the system (see below).

Example of logical architecture diagram presenting component assembly

Habilitation diagrams

Habilitation diagrams present a description of authorized services by role. This type of diagram is created using the icon.

Example of a habilitation diagram

Traceability diagrams

A traceability diagram presents the model's traceability relationships. This type of diagram is created using the icon.

Example of a traceability diagram showing processes, use cases and services

Use case diagrams

Use case diagrams describe the most important services provided by a system. From actors, they represents the most important scenarii of the system in question. This type of diagram is created using the icon.

Example of a use case diagram

Message diagrams

A Message diagram is created using the icon.

Example of a Message diagram