Oracle Sequences

Sometimes in the middle of the night you will be working on a conversion effort and you will need to populate a field with a sequence of values.  This is easily done using Excel but if you are dynamically loading data you may want to have a more flexible feature.  Oracle sequences have that ability.

Create A Sequence:

CREATE SEQUENCE adjustment_fix START WITH 1001 INCREMENT BY 1 NOCACHE NOCYCLE;

So this sequence will start are 1001 and each additional next value will by greater by 1 — so 1002, 1003, 1004….etc.  I had an oddball situation where I needed an 18 digit number that increased by 10000000. So in my case it was:

CREATE SEQUENCE adjustment_fix START WITH 300000000010000000 INCREMENT BY 10000000 NOCACHE NOCYCLE;

Now that you have the sequence, you need to populate the rows with the sequence.  So I created a temporary table and loaded all the values in the table.  Then I had another field for the sequence number.  I tried to insert the sequence while doing the insert into the staging table of the values I needed staged for the adjustment but it whined and complained.  So I did the insert and then did an update of the rows:

SQL:    UPDATE STAGING_TABLE_4_ADJ SET ADJ_SEQ = adjustment_fix.nextval;

BAM!  Now I have 2200 rows of adjustment data with a unique sequence number on each row so that I can load the staging data tables.

Audit Create Session Logins

I had an interesting security breach the other day where a developer who had sql access to the production environment gave out his access to basically “everybody”. There was a huge panic and at the end of the day, I found a tip from Burleson at dba-oracle.com that showed that you can easily turn on auditing for session creation and it gives a wonder account of the people that are failing to login because of the changed credentials.
First you need to set the audit parameters on and bounce the system if it isn’t.

audit_trail=true
audit_file_dest=’/dest/to/my/audit/logs/’

from SQL*Plus: audit create session whenever not successful;

Now when you query: Select * from dba_audit_trail; you will get a listing of the folks that have failed to create a session because of incorrect credentials.