In the past, Oracle said, for example, if you took 1z0-007 before 1 Sep 2003, but not all exams, you are still eligible to get certified even you have no taken any courses.
As my company paid for my Oracle training fees, and thus, I received the certification without any problems.
Also, other people suggest that, as the course requirement is only for Oracle9i and later versions, they rush to get Oracle8i DBA before 31 Dec 2004, and then take the upgrade exam. But now, Oracle8i has been retired, and thus, if you want OCP cert., course taking is a must.
But if you just want an OCA cert., what you need is to pass the exam only.
Nick
SCJP 1.2, OCP 9i DBA, SCWCD 1.3, SCJP 1.4 (SAI), SCJD 1.4, SCWCD 1.4 (Beta), ICED (IBM 287, IBM 484, IBM 486), SCMAD 1.0 (Beta), SCBCD 1.3, ICSD (IBM 288), ICDBA (IBM 700, IBM 701), SCDJWS, ICSD (IBM 348), OCP 10g DBA (Beta), SCJP 5.0 (Beta), SCJA 1.0 (Beta), MCP(70-270), SCBCD 5.0 (Beta), SCJP 6.0, SCEA for JEE5 (in progress)