Reading Vsam file in Batch program

Arun bv · New User Joined: 29 Dec 2010 Posts: 41 Location: Mumbai

when i read a vsam file using partial key in batch program it is showing record not found,but records were actually present in that Vsam file.

it has composite key having six fields and i intialized whole key first ,then populated first field with proper value,for the second field i moved low-values,populated third value,,i didn populate rest as im going to read the file with partial key..

but file status is 23...that is record not found

could anyone guess out on this...

enrico-sorichetti · Posted: Sat Jun 04, 2011 11:33 am

review a bit Your understanding of partial key
it must be a proper left substring of the full key
so if the full key is ABCDE You can start <browsing> using ...
A, AB, ABC, ABCD

using the three char case and _ as a low value You are trying to start browsing with A_C
and since that is not a proper left substring a NRF is what You get!

Bill Woodger · Posted: Sat Jun 04, 2011 11:47 am

When you say "read", do you mean START and READ NEXT? If you do, you will still get not found if the key for the START is higher than the last record on the file.

Arun bv · New User Joined: 29 Dec 2010 Posts: 41 Location: Mumbai

thanks enrico....

here the requirement is ,i wont know B,E,F in ABCDEF key....

so i have moved low-values to the whole key first...then i populated the fields which i have(i.e., populated A_CD__ in ABCDEF key) ....then read,,,,

so how to handle this case...

Bill Woodger · Posted: Sat Jun 04, 2011 11:51 am

START with A______. READ NEXT in a loop. Bytes 3-4 higher than part-of-key-you-know, stop, equal process and read next, lower, read next.

Arun bv · New User Joined: 29 Dec 2010 Posts: 41 Location: Mumbai

sry i forgot to mention

START GRP-V KEY >= GR-KEY

READ GRP-V

then read with partial key(in GR-KEY) .....

PeD · Posted: Sat Jun 04, 2011 11:57 am

Or stop for a few times and ask yourself : create - you or someone from design - alternate indexes if application requires that approach.

Data must be correctly placed to serve processes.

enrico-sorichetti · Posted: Sat Jun 04, 2011 12:00 pm

Bill Woodger · Posted: Sat Jun 04, 2011 12:03 pm

Bill Woodger · Posted: Sat Jun 04, 2011 12:12 pm

It is also pointless, re-read enrico's post, to set anything other than the left-most part of the key. The "left-most" can be anything, up to and including the entire key, but setting a bit of left-most and then something further off to the right is pointless and will confuse anyone maintaining your program in the future.

For your processing, set the left-most (or high-order) byte (from your example) and leave the rest as low-values. As already stated, do your lower-but-non-contiguous-key processing in a read-next loop. Don't forget file-status on all IO. Including START and READ NEXT. All, means ALL.

If your data is such that an alternate key would help (you or your analyst, immediate senior, whatever have to decide, but it must be a rational decision based on the data, not on trying to make the code in one program easier) then try to process file such that the input is in the same order as the alternate key.