RE: SQL Loader

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-----
Sent: Tuesday, June 03, 2003 6:00 AM
To: Multiple recipients of list ORACLE-L

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 <ORACLE-L_at_fatcity.com>       
                    yahoo.com>                    cc:

                    Sent by:                      Subject:     Re: SQL
Loader                                               
                    root_at_fatcity.com

 

 

                    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 <stephenandert_at_firsthealth.com> 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

>>> pradeep_at_ibsplc.com 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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