Jason,
Whilst it is possible to use R:Base currently (v7.6, at least) with the data
assumed to be in the order that it was added you should never rely on that
being the case.
In the Data Browser it can be a very useful happenstance but you must be aware
that the sequence _could_ be changed for some reason. Furthermore, RBTI may
need to change the way this happenstance works in the future.
Personally, I make great use of it but I also ensure that any program/command
uses an order by clause.
Larry beat me to the suggestion of using a view and all that I would add is to
remember that a temp view could be useful way of creating that view if your
selection is one that changes.
Regards,
Alastair.
From: Jason Kramer
Sent: Tuesday, March 23, 2010 2:55 PM
To: RBASE-L Mailing List
Subject: [RBASE-L] - Re: LISTOF question
Larry,
Thanks. That works. I never considered using a view because the table
is currently ordered (an unlikely to ever get out of order because the PK is an
autonumber). I just issued CREATE VIEW myview AS SELECT cols FROM mytable
ORDER BY mycol.
I still don't see why R:BASE does not sort the LISTOF. If I understand
the normal SELECT process vs. SELECT with an ORDER BY it goes like this:
NORMAL ORDER BY
Find all matches Find all matches
Display them as found Sort them
Display them
I though the sorting after all items are found was what caused the slight
delay when an ORDER BY clause is used. I though that a similar process would
be used with LISTOF
NORMAL LISTOF Order BY LISTOF
Find matches Find matches
Load into list Sort them
Display Load list
Display
Thanks,
Jason
Jason Kramer
University Archives and Records Management
002 Pearson Hall
(302) 831 - 3127 (voice)
(302) 831 - 6903 (fax)
On 3/23/2010 10:28 AM, Lawrence Lustig wrote:
<<
Should the results of a SELECT LISTOF be sorted if the SELECT command has
an ORDER BY clause?
>>
No. Think of what's happening internally in R:Base when you issue that
SELECT statement: R:Base is returning a result set with a single row
containing the result of the LISTOF function. The ORDER BY clause does, in
fact, order the result set but since that result set has only a single row in
it, there's not real meaning to the ORDER BY.
<<
If not, is there an easy to way to sort the resulting list, or would I have
to write a sort routine myself?
>>
First, create a VIEW on the table that contains an ORDER BY clause. Then
perform your LISTOF query against the view, rather than the original table.
--
Larry
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