× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.


  • Subject: Re: SQL Question (selection by RRN)
  • From: "R. Bruce Hoffman, Jr." <rbruceh@xxxxxxxxxxxxx>
  • Date: Thu, 14 Dec 2000 08:19:47 -0500

-----Original Message-----
From: Stone, Brad V (TC) <bvstone@taylorcorp.com>
To: 'MIDRANGE-L@midrange.com' <MIDRANGE-L@midrange.com>
Date: Tuesday, December 12, 2000 5:50 PM
Subject: SQL Question (selection by RRN)


>i'm playing with SQL, and I was under the assumption that when you select
by
>RRN that it should be very fast.  I'm finding that isn't the case.
>
>Any ideas?  I'm doing something like:
>
>SELECT CHAR(A.ODPERDSC) FROM CSODATA/OCSDETAIL A WHERE
> RRN(A) = 84201 FOR READ ONLY OPTIMIZE FOR 1 ROWS
>
>Takes a while.  (File is very large).   In other cases I've had great
>results.  Shouldn't RRN selection be BAM! right there?


You would think, wouldn't you? But note that RRN(correlation_name) is a
function. It is computed. So the request does a table scan and looks up the
RRN.

Direct access (which is what you are asking for) is not really defined in a
relational database. It was a side-affect in ISAM databases.

Also, note that when you create a table using SQL, the default is to re-use
deleted records. So a record that is in position 12 now, might not be later.

===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified Specialist - AS/400 Administrator
 -- IBM Certified Specialist - RPG IV Developer

"Those who would give up essential Liberty,
  to purchase a little temporary Safety,
  deserve neither Liberty nor Safety."

     - The Papers of Ben Franklin



+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---

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 1997-2024 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.