Project and Unit


Project and Unit

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A project is the basic management unit in StarUML™. A project can manage one or more software models. It is the top-level package that always exists in any software model. In general, one project is saved in one file.

Project Structure

A project contains and manages the following sub-elements.

Project Sub-Element



Element that manages one software model.


Element that manages models that express one subsystem.


The most general element for managing elements.

Project File

Project files are saved in the XML format with the extension name “.UML”. All models, views and diagrams created in StarUML™ are saved in one project file. A project may also be divided up and saved in multiple units. A project file contains the following information.

·UML profiles used in the project
·Unit files referenced by the project
·Information for all models contained in the project
·Information for all diagrams and views contained in the project


While a project is generally saved in one file, there are cases where one project needs to be saved in many smaller files so that a number of developers can work on the project together. In this case, the project can be managed as multiple units. A unit can have a hierarchical structure; it may contain many sub-units under it. Units are saved as .UML files and are referenced by project files (.UML) or other unit files (.UNT).

Unit Composition

Only package, subsystem and model elements can constitute one unit. All elements under these package type elements are saved in the respective unit file (.UNT).

Unit Hierarchical Structure

Just as a project can manage many units under it, a unit also can manage many sub-units. Since a parent unit has reference to its child units, all units have a hierarchical structure.

Model Fragments

A model fragment is a part of a project saved as a separate file. Only model, subsystem or package items can constitute model fragments. Model fragment files are saved with the extension name “.MFG”. Model fragment files can be easily included in any project at any time. Model fragments are essentially different from units in that once included in a project, they merge completely with the rest of the project.