The database when made in oracle 10g consists a minimum of
----Two datafiles on the two manadatory tablespaces system and sysaux
----Control file multiplexed or not (Oracle recommends three)
----two online redolog files with atleast one member each.

Apart from the physical componenets mentioned above orcale database also consists of
---password file,
---parameter file and or spfile,
---and other datafiles depending on the application.