deadlock demo: only one session is required (since it can have multiple transactions :)

single_session_deadlock.log

SQL> 
SQL> create table t(id, value) as select 1, 1 from dual;

Table created.

SQL> 
SQL> update t set value = value + 1 where id = 1;

1 row updated.

SQL> 
SQL> declare
  2  	 pragma autonomous_transaction;
  3  begin
  4  	 update t set value = value + 1 where id = 1;
  5  	 commit;
  6  end;
  7  /
declare
*
ERROR at line 1:
ORA-00060: deadlock detected while waiting for resource 
ORA-06512: at line 4 


SQL> 
SQL> drop table t purge;

Table dropped.

SQL> 
SQL> exit

single_session_deadlock.sql

set echo on 

spool single_session_deadlock.log

create table t(id, value) as select 1, 1 from dual;

update t set value = value + 1 where id = 1;

declare 
    pragma autonomous_transaction;
begin 
    update t set value = value + 1 where id = 1;
    commit;
end;
/

drop table t purge;

exit