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How to read KSDS file from bottom

 
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yasho_bala

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PostPosted: Thu Jul 26, 2012 12:57 pm    Post subject: How to read KSDS file from bottom
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How to read KSDS file from bottom,
i dunno key also, in that case how it is possible
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PeterHolland

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PostPosted: Thu Jul 26, 2012 1:08 pm    Post subject:
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Mainframe Skills: jcl,cobol,vsam ?????????????????
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yasho_bala

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PostPosted: Thu Jul 26, 2012 1:09 pm    Post subject:
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im jus learner...
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PeterHolland

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PostPosted: Thu Jul 26, 2012 1:34 pm    Post subject:
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This site is for starters :

http://ibmmainframeforum.com/
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Robert Sample

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PostPosted: Thu Jul 26, 2012 2:37 pm    Post subject:
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Terminology is critical in IT, where similar terms may mean very different things. A file does not have a "bottom", much less a "top". Assuming you meant that you need to read the file from the last record forward, there are two possible answers: if you are using CICS, you can -- possibly (if the file has a HIGH-VALUES key ending record) -- set the key to HIGH-VALUES, do EXEC CICS START, then do EXEC CICS READPREV twice to get the last record and repeat the EXEC CICS READPREV as needed; if you are using batch, then the answer is that it is not possible to read a VSAM file backwards in batch, period. CICS and batch use different methods to access the data, so batch does not support reading the file backwards.

If you don't know the key starting position and length, you will need to use IBM utility IDCAMS to generate a LISTCAT ENT(<filename>) ALL in order to get this required information.
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Anuj Dhawan

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PostPosted: Thu Jul 26, 2012 2:49 pm    Post subject:
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May be somewhat brutal method but with the kind of info we've in hand -- use some intermediate step(s) to copy the file in "reverse order" and work with this intermediate file.

Or load the data into a COBOL table, then process the data out from the table in reverse order. Well, this a concept - can this be implemented, well, it depends.
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Anuj Dhawan

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PostPosted: Thu Jul 26, 2012 2:53 pm    Post subject:
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On a second thought, is it an interview question?
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yasho_bala

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PostPosted: Thu Jul 26, 2012 5:40 pm    Post subject:
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yes, it is an interview question
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enrico-sorichetti

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PostPosted: Thu Jul 26, 2012 6:04 pm    Post subject: Reply to: How to read KSDS file from bottom
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moved as per previous post icon_cool.gif
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Anuj Dhawan

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PostPosted: Thu Jul 26, 2012 6:13 pm    Post subject:
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yasho_bala wrote:
yes, it is an interview question
There is a separate section for "Interview Questions" - if you've an interview question, please post it in that section going forward. It helps others to answer your question in a legitimate way. For example, some interview questions are just conceptual and those concepts might not be applied in practical scenarios. Having said that, I believe you've enough answers for your question. If you've more obsevations, post us back.

Please notice your question has been moved to "Interview Questions" part of the Forum.
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