Connections between model elements with regard to a certain aspect are modeled in a diagram by means of element relationships. You can use cross-diagram relationships in whiteboard diagrams.
Creating Relationships
Elements are related to each other in many ways. Most relationships are shown as edges (lines) in the diagram. Relationships express assignments, inheritances (generalization, specialization), dependencies, flows, compositions etc.
Non-directional relationships normally express binary associations (connections) which the direction is not set for.
Directional relationships consist of at least one source and one target. Directional relationships are normally shown as an arrow and the arrowhead points to the target. Important directional relationships include e.g. inheritance, realization, dependency, as well as aggregation/composition.
Configuration only allows a relationship in one direction; this means you can only create a relationship in this direction. This applies to inheritances and information requests, for example.
Reassigning Connections
To change the sequence or structure in a diagram, you can reassign a connection to another element that is allowed to have this kind of connection to the source element.
Modifying how Relationships are Displayed
The respective notation determines how relationships are displayed in a diagram. This also includes information about whether the edges are always shown as rectangular or whether they can be displayed as any number of polygonal lines.
You can see what type of edge is used from the mouse pointer when you hover over the edge.
| Mouse Pointer | Representation |
|---|---|
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The "move" pointer shows that you can define any number of edge points by clicking with the mouse and dragging an edge point to where you want. |
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The "change vertical and horizontal size" pointer shows that it moves rectangular edges but cannot create any edge points. |
If a relationship can be shown as any number of polygonal lines, then the following display options are available:
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Display with edge points that can be moved.
You can place the mouse pointer over the edge; this edge is selected and you can click on it and drag an edge point anywhere you want in the diagram. You can create any number of edge points and design the polygonal lines as you wish. You can only remove the outmost edge point by dragging it to the linked element.
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Rectangular display (as with edges that can only be displayed a certain number of ways)
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In order to achieve a right-angled display with a maximum of one edge point, press the [Ctrl] key and double-click on the edge.
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In order to achieve a right-angled display while retaining edge points, press the [Shift] key and double-click on the edge.
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Straight display with no edge points
Double-click on the edge to show it as a line.
Showing and Hiding Relationships
Existing relationships can be hidden in a diagram so that the diagram is easier to understand and not so busy.
Note
All relationships are always shown when defining processes and collaborations, as well as in diagrams for business object states. Always visible relationships cannot be hidden.
Select a participating element and select Design>Display>Relationships (Ctrl+Shift+R); the diagram interface is shown grayed.
Note
If no element is selected, all relationships are shown/hidden in the diagram.
Visible relationships to the element are shown in black. Hidden relationships are shown in gray.
Click on a relationship shown in black to hide it; it is then shown in gray.
Click on a relationship shown in gray to show it; it is then shown in black.
