An Oracle blog - Amardeep Sidhu » SQL

Delete Delete Faster Faster ;)

Sidhu — Thu, 08 Oct 2009 15:23:36 +0000

2-3 days ago, I came across a code, intended to make delete faster. Just have a look

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LOOP
SELECT COUNT (1)
INTO v_cnt
FROM table1
WHERE ROWNUM < 2;

IF v_cnt = 0
THEN
EXIT;
END IF;

DELETE FROM table1
WHERE ROWNUM < 1000;

COMMIT;
v_cnt := 0;
END LOOP;
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Missing grants

Sidhu — Mon, 03 Mar 2008 15:07:15 +0000

Today one of my colleague was working on a simple PL/SQL procedure. Based on some logic it was returning count(*) from all_tab_columns for few tables. It gave count incorrectly for one table out of around fifty in total. He just hard coded the table name and ran it but again it showed count as zero.

Then he took the code out of procedure and wrote it in DECLARE, BEGIN, END and after running it showed the correct count. But ran as database procedure it always shows incorrectly.

Finally just as hit and trial, he gave SELECT on the TABLE to database user [Table was in different schema], used to run the procedure and everything was ok. Isn’t it bit stupid

Update: Well, it happens for a reason. Nigel Thomas pointed out in the comment. The reason is that privileges granted to a role are not seen from PL/SQL stored procedures. You need to give direct grant to the user for this or another method is to define the procedure or package with invoker rights.

Thanks Nigel

Learning Regular Expressions

Sidhu — Wed, 27 Feb 2008 15:59:50 +0000

From Eddie’s blog I got a link to 3 posts on Regular Expressions on OTN written by CD. Wonderful stuff. Check out.

Part 1

Part 2

Part 3

& Thanks CD…wonderful work buddy !

Shell script to spool a no of tables into .xls files…

Sidhu — Tue, 26 Jun 2007 17:08:00 +0000

On OTN someone asked a question that how to spool data from a table into a xls file. Spooling a single table I discussed in one of the previous posts. We can use the same approach to spool data from more than 1 table also. Well here I will do it through a shell script and assume that you have a text file having list of tables to be spooled (Even if you don’t have one, it can be easily made by spooling the names of tables into a simple text file) Here is the shell script that you can use to spool data to various xls files, table wise.

cat list.txt | while read a
do
echo "spooling $a"
sqlplus username/password@string <<EOF
set feed off markup html on spool on
spool /home/oracle/$a.xls
select * from $a;
spool off
set markup html off spool off
EOF
done

I didn’t see any work around for Windoze as SQLPLUS << EOF thing doesn’t seem to work in Windows. Will try to find some alternative. If you come across something, do let me know.

Sidhu

Spool to a .xls (excel) file…

Sidhu — Fri, 15 Jun 2007 18:44:00 +0000

A small tip, I read on OTN about spooling to a .xls (excel) file:

It goes like this

set feed off markup html on
spool onspool c:\salgrade.xls
select * from salgrade;
spool offset markup html off
spool off

And the xls it makes shows up like:

Sidhu

Command line history in SQL (for Linux)…

Sidhu — Fri, 04 May 2007 15:05:00 +0000

Found a very interesting article on Dizwell’s blog. It was about keeping history of the SQL commands in SQL Plus on Linux. It is almost very simple. Just need to download a small utility called rlwrap from here. Its a tar.gz file. Download it, un-tar using

tar -xvf rlwrap-0.28.tar.gz

It will create a directory with the same name. cd to the directory and run

./configure

Now do

make install

(I was logged in as oracle user, then did su, but it gave some errors, finally I logged in as root and it worked fine)

Now what is left to be done is make an alias for sqlplus as

alias sqlplus='rlwrap sqlplus'

Using up/down arrows, commands can be scrolled up and down just like windows. Have a look at full article here.

Cheers

Sidhu