Tables missing after ALTER DATABASE CHARACTERSET

The charactersets in one of my databases was changed from UTF8 to AL32UTF8 to support some XML data. The change was performed by someone else by issuing 'ALTER DATABASE CHARACTER SET AL32UTF8; ' . There were no errors and the database came back up , but after some time I noticed that some of the tables that had CLOB datatype columns are missing - meaning the tables are totally gone. I am not sure if this is related to the characterset change - I hope it is not. What is the best way to find this out ? I do not have auditing turned on. Where can I check ? It is Oracle 11g.

Thanks.

You should start by looking in the dba_recyclebin and see if your tables are there. You can also look at your archive log files directory to se if a lot of archive logs were generated around the rime someone else was changing your character set.

I doubt that changing the character set would drop tables, but I suppose it could happen depending on the name of the tables in question and assuming that you went to a more restrictive character set and the names of those tables could not be directly represented by the new character set.

The new characterset is a superset of the old one, hence I am very confused. I do not find anything in DBA_RECYCLEBIN. This is not prod environment, so it is not running in ArchiveLog mode, so I do not have any traces either.
Any other suggestions ?

Thanks.