UML Diagrams Zicomi Systems publishes some UML example diagrams online from the world famous UML dictionary. more...
Version 2.5 Released Zicomi Systems is delighted to announce that version 2.5 of Zicomi Mentor is released. With support for UML 2.0 and all thirteen UML diagrams more...
Zicomi Systems' Director speaks about the UML at Objects by Design - an informative interview more...
Partner Programme Zicom Systems is delighted to announce a new world wide partner programme, become a partner today. more...
OMG Member Zicom Systems is made a member of the OMG!
Comment (Note)
A comment can contain textual information or graphical symbols that add additional information to a diagram or model. The information can take many forms from very formal, in the case of constraints, to conversational, in the case of working notes. Comments can be placed anywhere in a model or diagram, and simply by their proximity and alignment; they can be applicable to one or more elements. They may also be attached either to one or more elements by a comment attaching line.
Explanation
A comment is a semantically weak element. This gives the modeler lots of freedom with its usage. It can stand in isolation, or it can be attached to one or more model elements. It can contain just text, or graphics, or both. A comment can contain formal UML syntax in the case of the definitions of constraints and formal descriptions.
Important Points
A note may be attached to one or more diagram elements.
A note can be ambiguous if it is not obvious to the reader what its contents apply to. This ambiguity can be removed by attaching the note to the one or more elements, which it applies to, or by placing it in an unambiguous graphical relationship to the elements. By attaching the note to the elements you ensure that its relationship to the elements will be maintained, in the event that the diagram elements are moved or changed.
Unstructured text is semantically weak.
Unless you are using the note to specify a constraint or another formal condition the text in notes tends to be unstructured and even when it is attached to an element the connection between the note and the set of elements is weak.
A comment attaching line is related to a comment because it can be used to attach a comment to a model element. If the comment attaching line is not used the comment can stand freely in a diagram. A comment may be attached to any number of model elements. The comment attaching line like the comment has quite weak semantics.
