Error Stack and SQL trace

You can run the following to get an errorstack of any ORA error in a database:

alter session set tracefile_identifier =  'errorstack';
alter session set events '<error_id> trace name errorstack level 3';
--run the problematic sql here
alter session set events '<error_id> trace name errorstack off';

e.g. to diagnose error:-
ORA-00942: table or view does not exist
run:
SQL> alter session set events '942 trace name errorstack level 3';

To generate an sql trace, run the following:

alter session set tracefile_identifier =  'sqltrace';
alter session set events '10046 trace name context forever,level 12';
--run the problematic sql here
alter session set events '10046 trace name context off';