copy in reverse order



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copy in reverse order

Postby maxcc » Sat Jul 10, 2010 12:15 am

Hi,

How can we copy records in a PS to a PDS in reverse order without using sort?
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Re: copy in reverse order

 

Re: copy in reverse order

Postby dick scherrer » Sat Jul 10, 2010 12:43 am

Hello,

What is the reason for such a requirement?
Hope this helps,
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Re: copy in reverse order

Postby MrSpock » Sat Jul 10, 2010 5:55 am

I guess you'd have to load the data into a table, then write the data out from the table in reverse order.
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Re: copy in reverse order

Postby dick scherrer » Sat Jul 10, 2010 6:24 am

Hello,

Or create a table that has record number as the key and retrieve the rows using an ORDER BY ... DESCENDING.

Or define a vsam esds file that uses max-record-number - record-number as the key. The records would be written in reverse order.

And others, but i still wonder why the requirement to accomplish this without using sort. . .
Hope this helps,
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Re: copy in reverse order

Postby maxcc » Mon Jul 19, 2010 6:42 pm

Thanks for the replies.

It was an interview question. he said do it without using a key from a ps to pds.

not sure if reference modification option can work here.
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Re: copy in reverse order

Postby Robert Sample » Mon Jul 19, 2010 7:30 pm

Reference modification would only work within a single record.

Unless you use SORT (either directly through JCL or via a program), in general this cannot be accomplished.
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Re: copy in reverse order

Postby dick scherrer » Mon Jul 19, 2010 11:48 pm

Hello,

It was an interview question. he said do it without using a key from a ps to pds.
Sounds like there is/was some misunderstanding between the people in the room. . . PS and PDS datasets are not "keyed".

Maybe it is me that misunderstands. . .
Hope this helps,
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