delete command for oracle

hi..i got question here....
I'm using the oracle. when i using the SQL Plus, I type the command:
SQL> delete from ac_trx;
3 rows deleted.

SQL> select * from ac_trx;
no rows selected

That means all the records i've deleted.Then i close the SQL Plus.
When I relogin SQL Plus again, I type:
SQL> select * from ac_trx;
AC ACTX_DOORID ACTX_READE ACTX_TRXD
-- ----------- ---------- ---------
01 44184 24-NOV-03
01 44184 25-NOV-03

Why the records was still there?I've try many times already, the the records still there.

Thank you!

you need to commit after your delete, by typing 'commit;'

That correct! Thank you!