Pathmaker Programming Guide

Deleting Rows
How to Operate a DB Requester Application
067868 Tandem Computers Incorporated B–13
For applications that access NonStop SQL tables, if an error is encountered during a
DELETE BOX operation, all columns in error are highlighted and the application
displays the message associated with the first column in error in the message area.
The application will delete all rows that are error free.
The effects of a DELETE BOX operation can be reversed by requesting an UNDO
(shifted F13) operation immediately after the DELETE BOX operation.
DELETE Considerations for
Applications With
Several Boxes
When a parent row needs to be deleted, the end user will usually want to delete all
associated child rows, too. The procedure for this type of deletion is as follows:
1. Use any read operation to retrieve the row for the parent box.
2. Use an appropriate read operation to retrieve the row(s) for the nested box.
3. Delete the row(s) displayed in the nested box.
4. Repeat Steps 2 and 3 until the application does not return any rows as a result of
the read operation.
5. Delete the row in the parent box.
If the parent row had been deleted first, the application would not have been able to
read, and subsequently delete, the child rows; thus, deleting the parent row first
would leave the database inconsistent.