File: DBApplications.FigureCaptions

Figure 7-1. Each application implements displayer windows for one or more types of database entities.  Note that the type (domain) and name of the entity displayed is shown in the black bar at the top of each window, followed by a menu area in which commands appropriate to the particular type of entity are shown, followed by a display of information about the entity (tailored to the type).

Figure 7-1a. A message displayer, implemented by the electronic mail application.

Figure 7-1b. A month displayer, implemented by the calendar application.

Figure 7-1c. A picture displayer, illustrating graphic flexibility of the window display.

Figure 7-1d. A relation displayer (relations are entities, too).  Shows the attributes of the relation as columns, and the relationships in the relation as rows.

Figure 7-1e. A "whiteboard" displayer, providing a mechanism to spatially organize and browse through entities.  Note that icons appropriate to the entity type (month, person, message set) are shown.

Figure 7-1f. A "default" displayer, invoked when no application has registered itself to deal with entities of the type (the Organization domain, in this case).

Figure 7-2. Independent of domain, three types of windows may be implemented by an application: displayer, editor, and queryer windows.  Here we illustrate the three kinds of windows for the message domain.

Figure 7-2a. A message displayer, allowing message examination and browsing.

Figure 7-2b. A message editor, allowing creation of new messages to be sent or filed.

Figure 7-2c. A message queryer.  User fills in properties to search the database for matching messages.  

Figure 7-3. The user may browse through successive displayers by using the "mouse" pointing device to indicate entities he would like to see.  In this succession of frames (Figures 7-3a through 7-3d) he has browsed from a whiteboard to a message-set it contains, to a message in that set, to the sender of the message.  Each of these displayers is implemented by a different application, except for Figure 7-3d which is an instance of the default displayer.

Figure 7-3a. A whiteboard displayer, showing a number of entities in iconic form.

Figure 7-3b. A message set displayer, selected from the whiteboard in Figure 7-3a.

Figure 7-3c. A message the user selected from the message set in Figure 7-3b.

Figure 7-3d. The person who sent the message, selected from the message in Figure 7-3c.

Figure 4. The user may use various combinations of the mouse buttons and keys to invoke the same operations, regardless of the database application involved.  The yellow button was used for browsing in Figure 3; e.g. the message in Figure 4b could be obtained from the message set in Figure 4a in this way.  Note that the message selected in the message set is "grayed" to make it stand out.  More than one message may be grayed using the blue button to extend the selection to other messages.  Messages may be deleted from the set by pointing and using the control key and red button.  If a message is deleted directly by the DeleteMsg command in the message displayer, all displayers on the screen are automatically updated.  In this case, the message (Figure 4b) would then disappear from the message set in Figure 4a.  

Figure 4a. A message set displaying one line per message.

Figure 4b. A message in the message set of Figure 4a.

Figure 5. The Squirrel control window.  This allows a user or programmer to invoke application-independent database operations, such as aborting a database transaction or dumping all or part of the database to a text file.