Oracle instance and database question

Dear all,

This question will probably look simple and selfevident to you. I am newbies in Oracle world, I have until now worked only with MS SQL servers, so please execuse me.

The question is: Can an Oracle instance have more databases or it may have just only one?

In MS SQL you have server process and this process may serviced number of database. There is normal practice to create a new database whenever you want to separate data. It is perfectly normal to have 5 or more database on one server and the hardware requirement are the same as with one database with the same number of users. It seems to me that Oracle instance may have only one database and creating a new instance increases the hardware requirements (2 instances - double the hardware of the first instance). Is this true?

Any help is welcome

Thank you

	Ivo Sedlacek
	DCB, Actuaries and Consultants
	sedlace_at_dcb.cz