z/OS Block Mode Screen Design › Scrolling List › Scroll Protection Property

Scroll Protection Property

In the toolset, a protection property can be set for each scrollable repeating group view. The view can be unprotected to allow updates, or protected to prevent updates.

When the view is protected, the data view boundaries are defined by the data view, and not necessarily by the maximum cardinality of the view. The population of the data view can range from zero (an empty view) to the size of the data view extent. The population cannot be negative, and cannot exceed the size of the data view extent.

When a protected data view is used in scrolling, unpopulated fields are outside the boundaries of the data view. These fields are protected and blanked to prevent the user from entering data. This is especially true when scrolling in two or more fields is synchronized.

When the view is unprotected, the user can add an occurrence to the end of the view. The viewport can be positioned anywhere within the data view extent.

If the user enters data in a previously unpopulated area of the data view, and there are unpopulated rows before the row that was modified, then the view is condensed. The new data is moved to the first unpopulated row and the unpopulated rows are removed. All unpopulated rows are collected at the end of the data view.

Note: The data view protection property controls the selection of areas that can be mapped to the viewport and determines whether users can add a row to the data view. Screen Design also allows a field to be protected, thus preventing users from entering data. The combination of data view protection and field protection determines whether the user can change existing data, add new data to unpopulated rows, or both.

The following table identifies the possible protection level combinations and the result of each common action.