Bash date arithmetic

Not really oracle but useful nevertheless
date -d "yesterday" +"%d %B %y"


http://www.walkernews.net/2007/06/03/date-arithmetic-in-linux-shell-scripts/




Convert comma separated list into an array - dbms_utility.comma_to_table

Simple way to convert a comma separated list held in a single variable into its component parts.
pl/sql equivalent to php explode
e.g.

SET SERVEROUTPUT ON
DECLARE
l_list1   VARCHAR2(50) := 'A,B,C,D,E,F,G,H,I,J';
l_list2   VARCHAR2(50);
l_tablen  BINARY_INTEGER;
l_tab     DBMS_UTILITY.uncl_array;
BEGIN
DBMS_OUTPUT.put_line('l_list1 : ' || l_list1);

DBMS_UTILITY.comma_to_table (
   list   => l_list1,
   tablen => l_tablen,
   tab    => l_tab);

FOR i IN 1 .. l_tablen LOOP
  DBMS_OUTPUT.put_line(i || ' : ' || l_tab(i));
END LOOP;

DBMS_UTILITY.table_to_comma (
   tab    => l_tab,
   tablen => l_tablen,
   list   => l_list2);

DBMS_OUTPUT.put_line('l_list2 : ' || l_list2);



END;

http://www.oracle-base.com/articles/9i/UsefulProceduresAndFunctions9i.php

ON CURSOR FOR LOOPS

Oracle magazine article

Oracle Recycle bin and Flashback

To remove your own dropped object from the recycle bin do:-
PURGE RECYCLEBIN;

Alternatively issue
alter session set recyclebin=off ;

before dropping the object.

If you are important enough (i.e. have the privs)
Purge dba_recyclebin;
will drop all recyclebin objects.http://www.oracle.com/technology/pub/articles/10gdba/week5_10gdba.html

Parititions, global indexes - The magic "update indexes" clause

Global indexes need not go invalid when you change a table's partitioning if you use the magic 'update indexes' clause. Downside, it takes longer to perform the operation. Upside, users can continue to use the table without getting the error 'index is unusable'

All explained here :-

http://youngcow.net/doc/oracle10g/server.102/b14231/partiti.htm#i1006455
in the paragraph "Updating Indexes Automatically"

compression - gotcher number 1

You cannot drop a column on a compressed table.

Compression and bitmap indexes

When I first tried to compress an existing partitioned table with local bitmap indexes I got an error saying I 'could not compress the partition with a valid bitmap index' or word to that effect. I mistakenly took this to mean this was always the case. It appears that once the compress operation has taken place and the bitmap indexes rebuild from then on all will be OK and the erro does not reappear and this is the reason why :- http://stanford.edu/dept/itss/docs/oracle/10g/server.101/b10736/parpart.htm