Tracking the DDL (DROP) statements executed in a DB ?

Question

Hi ,
I had a requirement like tracking all the DDL executed in the DB. I used V$SQL to track the DDL statements.Also by joining V$SQL and V$SESSION using the ADDRESS and SQL_ADDRESS, i'm tracking the MACHINE and TERMINAL of the user who issued this command.
I was able to track all the DDL's except DROP.
I'm not able to track the ADDRESS for DROP in V$SQL.
The query I used,(this query is a part of the trigger that i'm using)
SELECT N.OSUSER,N.MACHINE,N.TERMINAL ,COUNT(1)
INTO V_OSUSER,V_MACHINE,V_TERMINAL,V_COUNT
FROM V$SESSION N, V$SQL S
WHERE
S.ADDRESS=N.SQL_ADDRESS
AND UPPER(S.SQL_TEXT) LIKE DDL_TYPE||'%'
GROUP BY N.OSUSER,N.MACHINE,N.TERMINAL;
I have two questions,
1)Why I'm not able to track DROP statements
2) How can I get the address of the DROP statements?

Answer 1

I think you are going about this the wrong way. The v$sql view (and related views) is essentially a view of a cache, not an audit mechanism.
Suggest you have a look at DDL audit triggers, most likely AFTER ALTER trigger. Note that these triggers also have numerous built-ins which provide contextual information which can be used as part of the auditing process.