UML Modeling Techniques > Constraints modeling > Constraints
  
Constraints
A constraint is a limitation imposed upon the functionality of a system. It has measurable and testable values. For more information about a Constraint, see Constraint (Dictionary Definition).
On constraint diagrams
Select the button on the Constraints Diagram toolbar to add a constraint to your diagram, or you can drag and drop a constraint from the dictionary.
When you have added a constraint, you can change it both via the diagram using the constraint Property pages or the context menu. With the Property pages you apply targets and values to your constraint.
On diagrams that are not constraint diagrams
Create or add Constraints to a diagram through the Constraint button. When you create a Constraint on a diagram, the Constraint is owned by the item that owns the diagram.
On the diagram, you can apply a Constraint to an item through the Link Note button – link the item to the Constraint. Note that if you delete the Link Note from the diagram, the Constraint will remain applied to the item.
In a Modeler pane
You can create a Constraint from most item types by right-clicking the item, pointing to New, and then clicking Constraint. When you create a Constraint from an item in this way, the Constraint is owned by the item. In addition, Modeler applies the Constraint to the owning item.