MIDRANGE dot COM Mailing List Archive



Home » MIDRANGE-L » February 1998

Re: re:RPG Trigger Pgm



fixed


RE:     Re: re:RPG Trigger Pgm

While on this subject I thought you'd might like to "Soft Code" the 96 byte
fixed portion of the first parm passed by the OS.  Here it is.

In this example the record length is 627 with 44 fields.

This is the D/S externally defined by the DDS below.
-----------------------------------
D PARM1      E  DS              EXTNAME(ETPFZ1) 
D*                                                                              
      
D       OLDREC          627                                                     
    
D       OLDNMAP         44
D       NEWREC          627
D       NEWNMAP         44
D*          
------           
OLDREC  = Before image 
OLDNMAP = Null mapping for the 44 fields (before image)
NEWREC  = After Image
NEWNMAP = Null mapping for the 44 fields (after image)



Here's the DDS                                                               
-----------------------
Field Name      Len     Type                                          
Z1FILE          10      A       File Name                            
Z1LIB           10      A       Library Name                         
Z1MBR           10      A       Member Name                          
Z1EVENT          1      A       Event - 1=Insert, 2=Delete 3=Update
Z1TIME           1      A       Timing - 1=After, 2=Before           
Z1COMMIT         1      A       Commitment Level                     
Z1RESERVE1       3      A       Reserved 3 Bytes                     
Z1CCSID          8      B       CCSID ID                             
Z1RESERVE2       8      A       Reserved 8 Bytes                     
Z1OROFF          8      B       Old Record Offset
Z1ORLEN          8      B       Old Record Length
Z1ORNBO          8      B       Old Record Null Byte Map Offset
Z1ORNBL          8      B       Old Record Null Byte Map Length
Z1NROFF          8      B       New Record Offset
Z1NRLEN          8      B       New Record Length
Z1NRNBO          8      B       New Record Null Byte Map Offset 
Z1NRNBL          8      B       New Record Null Byte Map Length
Z1RESERVE3      16      A       Reserved 16 Bytes
-------------------------------------------------------------------------
This is a very simple 'Plain Jane' example.  

You could parse out the before/after images by defining a field
that goes from byte 1 to xxxxxx  (whatever length you'd like as a 
max. maybe like 10,000 or whatever)  and then use a based pointer
to parse them out like David or Pete has shown using the Z1OROFF(etc)
fields(binary offset value) etc.
This way ALL your programs would use the same name & definition for 
all the Z1xxxx fields. 

John Carr
EdgeTech


-------------------------------------------------------------------------
Eric,

John is right about redefining using an externally defined data structure.  
Instead 
of the movel I would use a basing pointer.  You don't have to go way out of 
your 
way to do this and if your record is real long it can improve performance.  It 
may 
be a little more complicated but you can use the same code in every trigger you 
create.  In order to use the movel you would have to hard code the record 
length 
in your trigger buffer.  This is likely to introduce errors if the record size 
changes 
and you forget to change the hard coded record length.  Using a basing pointer 
you 
can simplify program changes when you add, change or remove a field.  The code 
would look something like:
...
     DRcdBuf         E DS                  EXTNAME(FILENAME) BASED(pRcdBuf)
...
     C                   EVAL      pRcdBuf     = %ADDR(TrgBuf + RcdOff)

David Morris

>>> John Carr <74711.77@compuserve.com> 02/11 4:42 PM >>>


RE: RPG Trigger Pgm

Eric
Don't bother with the offsets or SUBST business.  Movel the After image
into an externally defined data structure(Defined by the same file as 
being triggered).  Then you can manipulate the field names directly 
with EVAL's MOVE's Z-adds whatever you like(with compares, IFEQ etc) 
then MOVEL the externally defined data structure back into the Image
field.  or whatever.  why be complicated.

John Carr


     I'm trying to work up a sample DB trigger pgm (RPG) to validate 
     records at *insert and *update.  Documentation (DB2 for OS/400 
     Database Programming V3R7) indicates that I can modify the new record 
     image in the trigger buffer, but I can't see any way to apply changes 
     to the trigger buffer at offset value. For example, I want to update a 
     field RCDSTS to "SC04" to indicate the record contains errors before 
     writing a record to a Status History file. I can't see how to move 
     SC04 into the trigger buffer @ offset value corresponding to this 
     field. (<-- Huh? I think I just confused myself....)
     
     I guess I'm looking for the opposite of SUBST.. something that will 
     let me move a value into a field at location X. 
     
     Am I going to have to learn basing pointers or what?  Any hints, 
     suggestions, or samples would be appreciated.  Thanks.
     
     Eric A DeLong
     ericadelong@pmsc.com      

                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                            !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                            !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                                                                
                 !
                                                                                
                                                                                
                                      
+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to "MIDRANGE-L@midrange.com".
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---
uucp
+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to "MIDRANGE-L@midrange.com".
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---






Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2014 by MIDRANGE dot COM and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available here. If you have questions about this, please contact