Maintaining a read chain?
Thomson, Martyn EDUC:EX
martyn.thomson@gems1.gov.bc.ca
Fri, 03 Mar 2000 10:47:29 -0800
I have a simple one-record screen to maintain a SUSPENSE table. Access can
be sequential so user can page through the records. Each record has a list
of error codes, and by entering "ERR" in the Actionbar a design procedure
executes a "RUN SCREEN" command, passing the list of codes to a slave screen
to display error messages from a designer file.
My problem is, when user exits the error screen and returns to the main
screen, the read chain is lost and PageDown just starts over from the first
record, rather than displaying the next record. The slave screen must be
committing the Query transaction. How can I prevent that and retain the read
chain in the main screen?
I've tried using the TRANSACTION stmt to try to isolate the files in the two
screens; I've tried declaring the primary file as an aliased secondary, but
can't find a combination that works.
The Dictionary Transaction Model is Optimistic and dual i.e. Entry/Find
Model: Consistency, Select Model: Concurrency
Here's the relevant code -
SCREEN TRAX1424 ACTIVITIES FIND, CHANGE, DELETE
FILE SUSPENSE IN TRAX PRIMARY
ACCESS VIAINDEX KEY_SUSP_MARK_RESP_OCR_NO REQUEST STUD_NO
ACCESS SEQUENTIAL
...
PROCEDURE DESIGNER ERR
BEGIN
RUN SCREEN XTR$EXEC:TRAX233 PASSING T_ERR_CODES MODE F
END
SCREEN TRAX233 SLAVE RECEIVING T_ERR_CODES
FILE TAB_ERRORS IN TRAX DESIGNER
...
PROCEDURE INITIALIZE
BEGIN
;display first 15 error codes/messages; if more, prompt user to hit RETURN
for next page
LET T_REC_CNT=1
FOR 15
BEGIN
GET TAB_ERRORS VIAINDEX ERR_CODE USING T_ERR_CODES[T_REC_CNT * 3 -2:3]
OPT
IF ACCESSOK
THEN BEGIN
LET T_ERR_MSG = ERR_MSG OF TAB_ERRORS
DISPLAY T_ERR_MSG
END
LET T_REC_CNT=T_REC_CNT + 1
END
Is what I'm trying to do possible? All comments/suggestions welcome.
I'm using 7.10G1 for OpenVMS, and Rdb 7.0
Martyn Thomson
Ministry of Education, BC
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