Unprepared forms

There are two rules that one has to know when preparing forms: one is obvious and one is less obvious. The obvious rule is that a form has to be prepared after adding a field or a trigger to it (a form does not have to be prepared if a procedure or report is added for direct activation).

The less obvious rule is that if one adds a table to a form, a table that was not previously defined on that form, then every form that is built on that table has to be prepared.

An example: I was asked to add the status of a purchase order line to the form DOCPORDI ('choose order items', a sub-form of DOCUMENTS_P, 'Goods Receiving Vouchers'). This form is built on the PORDERITEMS table; the order line status description can be found in PORDISTATUSES, and one has to use the PORDERITEMSA table to connect between these two. Thus one would add the following lines to the form

PORDERITEMS.ORDI = PORDERITEMSA.ORDI, identifier 5?
PORDERITEMSA.PORDISTATUS = PORDISTATUSES.PORDISTATUS (identifier 5 on both sides)
PORDISTATUSES.PORDISTATUSDES to be displayed, identifier 5

First of all, the identifier 5? is used to introduce the PORDERITEMSA table - 5 because it is not an original table of this form, and ? because not every line in the PORDERITEMS table has a corresponding line in PORDERITEMSA (e.g. not every line has a status). The identifier 5 has to be used with PORDISTATUSES because this table too is not original.

Obviously, DOCPORDI has to be prepared, but also any form built on the tables PORDERITEMSA and PORDISTATUSES has to be prepared (i.e. the forms PORDISTATUSES, PORDIORDI and ORDPORD), even though no changes have been made to these forms. If there are many forms that have to be prepared then of course it's best to run the 'prepare all unprepared forms' program.

How does one know specifically which forms have to be prepared? This is a question that I have often wanted to ask, and a few weeks ago I found the answer. A simple SQL query would be

SELECT EXEC.ENAME
FROM EXEC, EXECPREPLOCK
WHERE EXEC.EXEC = EXECPREPLOCK.EXEC
AND EXEC.TYPE = 'F'
AND EXECPREPLOCK.UPD <> 'N'
FORMAT;

I have built a very simple report based on this query and added it to the scheduler so that I would receive a report every 15 minutes if there is an unprepared form anywhere in the system. I have found that it's better to reprepare any forms that appear in this report as opposed to simply preparing  them. I don't know what the difference between preparing and repreparing is, except that the latter is 'stronger' and takes more time. This always reminds me of a scene in the film 'A few good men', when Demi Moore objects to something in the trial, then strenuously objects. This results in a sarcastic remark from Kevin Pollak (I forget the exact wording); if preparing a form doesn't work then reprepare it.