I am making Oracle Insight application.

And it seemed someone make some change to databases and caused trouble.

I was asked to investigate about that.

audit_trail is set to DB

And there are many records in sys.aud$.

But, I saw  sys.aud$ table but, SQLtext or most of other columns are NULL.

So, I also

ALL_DEF_AUDIT_OPTS table.

but there was no audit setting.

I would like to know what is Oracle 11g DB default install audit setting, and

current audit setting is changed from initial DB installation or not.

What shoud I do that ?