A connectable is a special kind of symbol element that defines an area around the symbol that the incoming role lines connect to. Normally Connectables are not shown as part of the symbol in the editors, but in the Diagram Editor they are shown briefly during the relationship creation, marking the connection possibilities on the objects.

A connectable consists of two parts: a target point and an optional connectable edge. The target point is the position at which the role lines connecting to the symbol are aimed at. The target point is shown as a red circle with a cross hair. The connectable edge is displayed as a red polyline around the target point. Role lines stop where they intersect the connectable edge. If no connectable edge is defined, the role lines stop at the target point. Such point Connectables are mostly used in Relationship symbols that only have text elements, as then all role lines meet in the middle of the relationship.

There are two ways to create Connectables, one for a connectable with an edge defining where roles stop, and one for a point connectable with no edge.

To create a connectable with an edge:

To create a point connectable, i.e. a connectable without an edge:

Often Connectables must be defined according to or around a certain symbol element. To do this, select the element and choose Generate Connectable from its pop-up menu. This will create a connectable with an edge that fits around the selected symbol element.

Finally, as each object or relationship symbol must have at least one connectable, a default connectable is generated if no connectable has been defined when symbol is saved.

Editing a connectable is also a little different from other symbol elements. To select a connectable, you have to click the left mouse button exactly on top of the target point. To move the target point and the edge, first make sure that the connectable is not selected, then press and hold down the left mouse button on top of the target point and drag the connectable to the new location. If you want to move only the target point, select the connectable first, then press and hold down the left mouse button on top of the target point and drag the target point into the new position. The target point moves, but the edge polyline remains in the original position. It is also possible to move or resize the connectable by changing the settings on the Location and Size tab in the Connectable’s Format Dialog.

For other editing purposes, Connectables follow the behavior of polyline elements. You can make a connectable open or closed by toggling the Close menu item in its pop-up menu. To edit individual breakpoints of the edge polyline, select Edit Points from the pop-up menu. For more information about these commands, see Section 3.2.5.

The target point of the default connectable is used as the center of objects or relationships when positioning them in a Diagram Editor. For instance, when an object is aligned to a grid, the target point of the default connectable is placed on a grid point. Similarly, when a relationship is straightened, the target point of its connectable is placed at the intersection of its role lines.

On the Connectable tab (as shown in Figure 3–14) in the Format Dialog for Connectables, it is also possible to set two behavioral aspects of target points. The first one is the Sticky targetpoint setting, which controls what happens when the mouse cursor is brought on top of the connectable during the relationship creation in Symbol Editor.