Pathmaker Programming Guide

Undoing an INSERT, DELETE, or UPDATE (Shifted F13)
How to Operate a DB Requester Application
B–16 067868 Tandem Computers Incorporated
Undoing an INSERT,
DELETE, or UPDATE
(Shifted F13)
The effects of an INSERT, DELETE, or UPDATE operation can be reversed by
requesting an UNDO operation. An UNDO operation can be requested by pressing
shifted F13.
Undoing a DELETE
Operation
To undo a DELETE operation, the application must insert the deleted row(s). The
application can insert the deleted row as long as the end user has not requested
another DELETE, INSERT, UPDATE, or READ operation since the DELETE operation
that needs to be reversed was requested (and as long as another application has not
inserted the deleted row).
The end user can UNDO a DELETE operation even if the application does not support
INSERT operations.
Undoing an UPDATE
Operation
To undo an UPDATE operation, the application must replace the old row(s). The
application can replace the old row if the following statements are true:
Another DELETE, INSERT, READ, or UPDATE operation has not been requested
since the UPDATE operation to be reversed was requested.
Another application has not modified the updated row.
The end user can undo an UPDATE operation even if the primary key was changed.
Undoing an INSERT
Operation
To undo an INSERT operation, the application must delete the row(s) inserted. The
application can reverse the INSERT operation if the following is true:
Another DELETE, INSERT, READ, or UPDATE operation has not been requested
since the original INSERT operation was requested.
Another application has not changed or deleted the inserted row.
The row(s) were not inserted in an Entry-Sequenced table. An application cannot
delete a row from an Entry-Sequenced table.
The end user can UNDO an INSERT operation even if the application does not
support DELETE operations.