To open the specification of a graph type, press the Open toolbar button or choose Graph | Open... from the menu bar. You can also open a graph type from the lists in the Type Browser, Metamodel Browser, or Types Manager, or the Subgraphs tab of another Graph Tool.

To view the components that belong to the graph definition, press the Types tab button in the Graph Tool. The Types tab (cf. Figure 2–3) shows three lists that include all the object, relationship and role types of the current graph type.

Types can be added, deleted or edited by selecting the type and choosing the appropriate operation from the pop-up menu. The changes are not destructive: if you delete a type, then any instances of that type that are already in existing graphs will remain intact; but new ones cannot be added.

To specify how the relations, roles, ports and objects are connected to each other press the Bindings tab button. The components of bindings can be added, removed and edited. As with the types, the removal of types from bindings does not destroy existing bindings in graphs, but new bindings must be legal according to the new definition.