RE: VARLEN field... what good are they?

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Brad,

Just a few points regarding the code sample in your note.

1/ Define the length as Integer not Binary.  That will avoid numeric truncation 
that occurs 
with RPG's implementation of binary.  Especially since your field length could 
be 31000 and an 
RPG BIN(2) maximum value is 9999.  Better check your data, eh?

2/ %trim(%len(TEXT)) should be %len(%trim(TEXT)) although making the field 
VARYING may avoid 
the requirement to use %trim.

3/ CPYF will cope with VARCHAR fields when the copy is performing:
        o source-varchar-field to target-varchar-field
        o source-varchar-field to target-fixed-field
but it has to make a best guess when source-fixed-fields are copied to 
target-varchar-fields.  
That guess is the fixed-length and is acceptable when you are copying 
fixed-fields which are 
smaller than the maximum length of the varchar-fields but is not so helpful 
when the 
fixed-field is the same size or larger than the maximum length of the 
varchar-field.  The Data 
Management guide has a section on these details.

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> X-Mailer: Internet Mail Service (5.5.2448.0)
> Date: Mon, 17 May 99 11:01:04 -0500
> From: "Stone, Brad V (TC)" <bvstone@taylorcorp.com>
> To: "'MIDRANGE-L@midrange.com'" <MIDRANGE-L@midrange.com>
> Reply-To: MIDRANGE-L@midrange.com
> Subject: RE: VARLEN field... what good are they?

------- Stuff deleted --------------------------
 
> So, in my case, I had a field that was max of 31000 bytes, and wanted to
> specify at least 64 bytes.  So I specified...
> 
>  A            MHDATA     31000          VARLEN(64) TEXT('Message Data') 
> 
> This says min of 64 bytes, max of 31000.  When updating the field in an RPG
> program, I had to do the following.
> 
>  D                 DS                      
>  D MHDATA                  1  31002        
>  D  MHDATALen              1      2B 0     
>  D  MHDATAText             3  31002        
>   *                                        
> 
> When I filled the field I had to say
> C             eval    MHDATALen = %trim(%len(TEXT))
> C             eval    MHDATAText = TEXT
> 
> Only then did it seem to not allocate all the needed space.  
> 
> The problem I was having before was that I changed the PF and then did a
> copy file and I expected it to know my field sizes.  Well, it didn't and
> assumed they were all 31000.
> 
> Seems cumbersome, but in this case it might be worth the space saved since
> the max size is so large.
> 
> Bradley V. Stone
> Taylor Corporation - OASIS Programmer/Analyst 
> bvstone@taylorcorp.com

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