I still am not sure why this was there in the first place, Chuck. Granted, yes, you can do what you've described. Personally, even I wouldn't probably go to inserting lines this way - SEU doesn't have a way to directly set sequence number, anyhow.

Interesting, though - but I guess I'm still interested in the use case that suggested it be done - I'm not THAT old on the 38 or 400 or successors that I'd know about the earlier systems.

Again, just curious.


On 9/24/2015 3:08 PM, CRPence wrote:
On 24-Sep-2015 13:36 -0600, Vernon Hamberg wrote:

Just ran into some keyed source PFs on our system - not all, just
some (probably) older ones.

So I've never even considered the possibility - is or was there a
reason for this?

Anyone more geezerish than I who remembers? Or knows?


Because that is supported :-) Supported, both in a DDS-described PF-SRC or a LF-SRC. Or more conveniently [without having to code the DDS source], a parameter is available on the Create Source Physical File (CRTSRCPF), the Access Path Type (ACCPTH). The default for that parameter is *ARRIVAL but the parameter specification of *KEYED is supported; the effect is to assign the Source Sequence (SRCSEQ) field as the one key of a non-unique keyed access path.

I have used that feature, almost exclusively, to allow for adding rows sequentially to the end but to appear positionally [by key] wherever they are necessary and for modifying rows to reposition the data [thus also Allow Delete (ALWDLT) and Allow Update (ALWUPD) also set to *YES]. Thus for a DDS-PF source, I can insert a row to add a new field between others by specifying an appropriate sequence number, or I can change the order of the rows and thus the order of the fields within the RcdFmt simply by modifying the sequence numbers, rather than by physically modifying the rows or deleting and then re-inserting rows of the source.

As an Amazon Associate we earn from qualifying purchases.

This thread ...


Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2022 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.