I'm looking for something like "Oracle database express" to be used on a mac. I hope this question won't offend anyone though. I'm absolute beginner on sql.
Your suggestions are most welcome.
Currently Oracle does not support MacOSX. They did for Tiger but dropped support plans for Apple when they bought SUN Microsystems. If you are willing to install an older version of MacOSX you can install Oracle 10.1.0.5 (fully featured) or 10.2.0.4 (incomplete). For now: forget it.
What you can do is run 11g on vmware. I have it running on macs using Parallels and VMware and they both work ok.