RE: Merge command
- From: "Vishal Gupta" <vishal@xxxxxxxxxxxxxxxxx>
- To: <genegurevich@xxxxxxxxxxxx>, "oracle-l" <oracle-l@xxxxxxxxxxxxx>
- Date: Sat, 12 Jan 2008 00:14:50 -0000
Also keep in mind that if there are any null columns in a unique index based on
which you are merging, then MERGE will fail on unique constraint voilation. You
can avoid this by using NVL(col1,0) on nullable columns. I am working on a
central repository of statspack to consolidate statspack data from various
databases into central statspack repository database. I faced this problem on
STAT$SGASTAT for nullable pool column.
MERGE table1
using table2
on (col1=col1 and NVL(col2,0) = nvl(col2.0) ).....
Regards,
Vishal Gupta
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of genegurevich@xxxxxxxxxxxx
Sent: Thu 10/01/2008 20:39
To: 'oracle-l'
Subject: Re: Merge command
Thank you , Louis, Jonathan, Greg and sol beach . Really appreciate your
responses.
I don't think I will be able to use the external tables due to the fact
that the input files are located on a
remote server. Regarding the Merge command itself, are there any specific
tuning actions I need to
do? Usually for an insert I try to drop the indices , do the insert,
rebuild the indices. For an update,
I do keep the indices. Merge is a combination of the two, so I am leaning
towards keeping the indices
on , is that reasonable?
thank you
Gene Gurevich
"Jonathan Lewis"
<jonathan@jlcomp.
demon.co.uk> To
Sent by: "'oracle-l'"
oracle-l-bounce@f <oracle-l@xxxxxxxxxxxxx>
reelists.org cc
Subject
01/10/2008 01:13 Re: Merge command
AM
Please respond to
jonathan@xxxxxxxx
emon.co.uk
If you have any uniqueness constraints on the table
then you need to be sure that the merge command
will not try to break those constraints, or the whole
merge will fail and rollback.
The obvious example is where you might have two
rows with the same primary key in the flat file that
needs to be inserted - but if you have other unique
keys declared the problem becomes a little more
awkward.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
----- Original Message -----
From: <genegurevich@xxxxxxxxxxxx>
To: "'oracle-l'" <oracle-l@xxxxxxxxxxxxx>
Sent: Wednesday, January 09, 2008 11:01 PM
Subject: Merge command
> Hi all:
>
> I am running v 10.2.0.3 and looking to using the MERGE command to load
data
> from a flat file. Some of the rows
> in the flat file are new and needs to be inserted into a fact table,
other
> - need to replace existing ones.
> I am planinng to have the application team load their file into a staging
> table via SQL*Loader and then load
> the data into the fact table via MERGE command. I have not used this
> command before; are there any issues
> that I should be aware of in terms of performance or bugs?
>
> thank you
>
> Gene Gurevich
>
>
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