AW: AW: Logical file keyed by active RRN

>>True.  But if you just have to read it by rrn...

... a SETLL and sequential READ will be the better solution.
(But in the original idea was to prevent from reading deleted records and
that's not possible)

Replacing all native I/O through embedded SQL is not always the best
solution.
Native I/O and SQL must COEXIST!

Birgitta

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"HauserSSS" <Hauser@xxxxxxxxxxxxxxx>
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AW: Logical file keyed by active RRN






Hi Rob,

your statement will cause the worst performance you ever had.
Because it is not possible to generate an index over the RRN.
The use of the built in function will always cause a table scan (including
all deleted rows!).

SELECT RRN(SHEA), MYFIELD
FROM ROB/SHEA
ORDER BY RRN(SHEA)
....+....1....+....2....+....
       RRN ( SHEA )   MYFIELD
                  1      A
                  3      C
********  End of data  ******

Rob Berendt
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"David C. Shea" <dshea@xxxxxxxxxxxx>
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Logical file keyed by active RRN






I want to create a logical file where the key is RRN.  I only want
active records listed in this logical.



The goal here is to be able to SETLL by key of RRN and have the pointer
positioned either at the next record in the file or EOF.



This is for a situation where there could be millions of deleted records
in the file.  Doing a regular SETLL by RRN and a READ could end up
scanning thru millions of deleted records.



Doing a SETLL on a logical file _keyed_ by RRN might do the trick.



Any thoughts??







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