The Graph Editor

To start the Graph Editor, choose the menu item Browse from the Workbench and select Graph Editor. The Graph Editor will start up and establish a connection to the same server as the workbench, if the workbench is currently connected. You can establish additional connections from within the Graph Editor application. If the Graph Editor has established the connection and loaded the initial data (note: this takes about 10 seconds), you can add an object to the editor window by clicking on the ``Load object'' button. An interaction window appears, asking for an object name. After entering a valid name (e.g. Employee) the Graph Browser displays the corresponding object. By clicking the left mouse-button, every displayed object can be selected. A selected object can be moved by dragging the object with the left mouse-button pressed. By clicking on the right mouse-button, a popup-menu will be shown with the following operations:

• Toggle component view
  switches the view of this object. In the detailed component view, you can either see the frame of this object or tree-like representation of super- and subclasses, instances, classes, and attributes of this object.
• Super classes, sub classes, classes, instances
  for each menu item you can select whether you want to see only the explicitly defined super classes (or sub classes, etc.) or all super classes including all implicit relationships. The query to the ConceptBase server to retrieve this information will be done when you select the menu item. So, the construction of the corresponding submenu might take a few seconds.
• Incoming and outgoing attributes
  The Graph Editor will ask the ConceptBase server for the attribute classes that apply to this object. For each attribute class, it is possible to display only explicit attributes or all attributes as above. The attribute class ``Attribute'' applies for every object and all attributes are in this class. Therefore, all explicit attributes of an object will be visible in this category.
• Add Instance, Class, SuperClass, SubClass, Attribute, Individual
  These menu items will open the ``Create Object'' dialog where you can specify new objects that should be created in the database. Note, that these modifications are not performed directly on the database. The editor will collect all modifications and send them to the ConceptBase server when you click on the ``Commit'' button.
• Delete object from database
  This operation will delete the object from the database. As for the insertion of objects before, the modification will be send to the server when you click on the ``Commit'' button. Note that this operation has an effect on the database in contrast to the next operation.
• Remove object from view
  The object will be removed from the current view. This operation has no effect on the database, i.e. the object will not be deleted from the database.
• Display in Workbench
  This operation will load the frame of the object into the Telos editor.
• Show in new Frame
  A new internal window (within the Graph Editor) will be shown and the selected object will be shown in the new window.

Exercise 3.6:
Start a GraphBrowser, and load "Employee" as initial object and experiment with the menu options available.