Re: LogicalFile SST KeyWord

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Venu,

'N' means the field is NEITHER for input nor output.  It will not appear in the 
program buffer.  Here is what 
the DDS Reference has to say:

    N (Neither)
       If position 38 is N, the field is a neither field (neither input nor
       output) and is valid only for join logical files. A neither field can
       be used as a join field in a join logical file, but your program
       cannot read a neither field.

       Use neither fields when the attributes of join fields in the physical
       files do not match. In this case, one or both join fields must be
       redefined.  However, you may not want to include the redefined fields
       in the record format (that is, you may not want the application
       program to see the redefined fields). Therefore, code the redefined
       join fields as N and they do not appear in the record format.

       A field with N in position 38 does not appear in the buffer used by
       your program. However, the field description is displayed with the
       Display File Field Description (DSPFFD) command.

       Neither fields cannot be used as select/omit or key fields.

Their purpose is to allow joining on parts of a field.

Your problem cannot be solved by the database.  You cannot update a substringed 
or concatenated field because 
they are logical fields that don't really exist in the database.  The value is 
created by database when you 
read a record.

It would be possible for IBM to use the SST and CONCAT information and update 
the underlying fields using 
your data values and the starting and ending position information but it 
doesn't work that way.  The effort 
expended to support something like this is not warranted by the demand.

You will need to write code to update the underlying physical file using a data 
structure to substring the 
field.

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> MIME-Version: 1.0
> Date: Fri, 05 Feb 99 15:20:14 -0500
> From: "VENU YAMAJALA" <venu_yamajala@goodyear.com>
> To: MIDRANGE-L@midrange.com
> Reply-To: MIDRANGE-L@midrange.com
> Subject: LogicalFile SST KeyWord

> 
> Ri All,
> 
> When LogicalFile Keyword SST is used we have to specify 'I' or 'N' in the 
>usage
> column. If we specify 'I' we cannot write or update data in this SST field. My
> requirement is that I have to update the SST field. Is there any way to do
> this? What is the other 'N' in the usage column? When I tried using 'N' in SST
> field, I got compile error saying "Characters in indicated field not allowed -
> Keyword or value not valid for usage or constant field".
> 
> Thanx in advance for any help.
> 
> Vg

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