If SQL loader loads a table it takes the first record in the file and stuffs it in the top of the table... like a stack... last in, first out.... so if you were to read the table like you read the sequential file, it is in there with the "bottom" record in the file as the "top" row in the table...so SQL loader is, in effect, "going" from the first record in the file, it just pushes it on the stack... and when you are reading you are popping it off (although leaving it physically in place where a stack would pop it off and then discard it). I haven't really played a lot with external tables, but I would imagine that Kirti's explanation is quite logical. It takes the first block of records in the external table, and inserts it as the first (or next if you are appending it) block in the "regular" table... so it appears to be in the "correct" order. I guess that, in a sense then, that external tables are more of a queue type structure... filling up top to bottom...
ajw
April Wells
Oracle DBA/Oracle Apps DBA
Corporate Systems
Amarillo Texas
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-----Original Message-----
From: Pradeep Kumar G [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 03, 2003 6:00 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: SQL Loader
When I queried the table to which SQL Loader loaded data from the .dat
file, the first record in the table was the 50000th record and
49999,49998...........
Kirtikumar Deshpande
<kirtikumar_deshpande@ To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
yahoo.com> cc:
Sent by: Subject: Re: SQL Loader
[EMAIL PROTECTED]
06/02/03 11:02 PM
Please respond to
ORACLE-L
I think the query is displaying data from the table in the order in
which rows were inserted by SQL*Loader.
Whereas, the query to read the same data from the external table is
reading the file from the first physical record. So it appears
reversed..
- Kirti
Stephen Andert <[EMAIL PROTECTED]> wrote:
Pradeep,
I don't know what you mean when you say SQL*Loader is "starting from
the 50,000th record and going up". If there are 50k records, are you
saying it is not loading them? Or is it reading them from 50,000 then
49,999 (i.e. in revers order)? How are you determining what order
they
are being read?
Regarding external tables, the way they work is by reading the file
from the first block to either the end or till it finds what it
needs.
Thus, external tables will read in the order the records are in the
file.
I stand ready for my ramblings to be corrected by anyone who can
explain better :)
Stephen
>>> [EMAIL PROTECTED] 06/01/03 10:35PM >>>
Dear All,
I don't know whether SQL Loader behaves like this always or for me
only. I am loading a .dat file which has 50000 records.
I noticed that S! QL loader is starting from the 50,000th record and
going upwards, while external tables is starting from the 1st record
and going downwards.
Could somebody help me confirming this?
Regards,
Pradeep
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