Links

§1 Maintaining links

If you have read the Introduction to dBase, you are ready to learn the specific details on the maintenance of the links required for the effective management of your data. Specifically, how to create and delete anonymous and qualified links between any two elements of the Zator's data structure.

§2 Create Links

The procedure is very simple and consists of two phases. The first is to define who will be the source, who the target, and who eventually the qualifier (type) of the new link (the latter is only necessary if the link is to be qualified). The second, the fastest and easiest, is to create the link. To this simply need click on the corresponding button.

	Create an anonymous link. Notice that this button is only enabled if you previously selected an source and a target.
	Create a qualified link. In addition to the above conditions, have selected an source and a target, you must also have chosen a type (qualifier).
	Create inverse anonymous link (the item selected as the source is taken as the target and vice versa)

As for the first part (selecting members involved with the link), it is equally easy, but it requires a bit of navigation. You should be placed in the corresponding item (make it actual) and select it as source, target or type. Usually the latter operation can be done in two ways: with the appropriate option from the context menu or using the buttons on the toolbar.

	The item that has focus on the main window is selected as the source for the proposed link.
	The item that has focus on the main window is selected as type (qualifier) of the proposed link.
	The item that has focus on the main window is selected as target of the proposed link.

§3 Conditions

Zator allows the creation of links between most parts of its data structure, although the creation of new links is subject to certain limitations, some of logical type, whose justification is obvious.

The link elements must belong to the same area of connection. I. e, it is not possible to establish a link between an atom of dBase and a item of the Planner at a time when both zones are using different work areas.
The source and target can not refers to the same element (an item can not link with itself).
In the case of qualified links, the qualifier can not coincide with the source or target. That is, the three elements of the link: source, target and type, should be different items.
There can't be a link of any kind between two items (source and target) if previously there was any link between the two in the same direction (same origin and destination) [1]. I.e., if there is an anonymous link A > B, it is not possible to establish the qualified link A > B and vice versa.
Only the items (atoms) of the main windows can be used as link qualifiers.
The items of the Planner (Appointments; Expiry Dates; Pending tray, and Events) and the ones of the Messaging system (Sent messages; messages Inbox and messages Outbox) can only be used ad target for a link (can not be used as source).

§4 Delete links

During the session, and while did not change the work area, Zator keeps memory of the last anonymous and qualified link which have been created and there is a possibility of delete them directly thru the buttons arranged by on the toolbar.

	Delete the last anonymous link created.
	Delete the last qualified link created.

It is appropriate to recall here that the elimination of a link has no effect on the elements (items) involved in it, that still exist. However, the reciprocal is not true, the removal of an item it affects the links in who it intervening; the links wherever it appears as source or target, are eliminated, and those on who appears as qualifier, becomes anonymous.

The deletion of those links different of the last created, should be made in the lower windows of the dBase tab. The process was explained in contextual menu in the window of links, and here we only remember that to delete an item of these windows (a process that there is named delete link or anonymise link) refers to the links themselves, not the items involved.

§5 Auxiliary utilities

To facilitate the maintenance of the links, Zator retains memory of the last 20 items selected as source, target and type, and the possibility of bring them back as the current selection without having to revisit the appropriate item. Also can be checked which item is currently selected for each of the above functions (source, target and type).

These options are accessed from the menu displayed by the split buttons next to the main ones. Note that the result of the options to view source; view type and view target selected, are shown in the status line.

Top.

[1] Note that the existence of a link A > B is not an impediment to the creation of another link A < B.

Top