Re: Basic Oracle Concepts

newbie wrote:

> 1) Every RUNNING database is associated with an Oracle instance. But is it
> possible to create > 1 databases in the harddisk while allowing the instance
> to select the specific one to be mounted during database startup? If yes,
> is it by specifying the init.ora to be used in 'STARTUP'?

You need to better understand the words you are using and their meaning.

A database, in Oracle, is physical files, datafiles, undo files, tempfiles residing on a hard disk along with their associated control files and log files. They have nothing to do with a specific installation of the Oracle binaries and nothing to do with the Oracle program code executing in memory.

The Oracle program code, executing in memory, is an Instance. And multiple instances can connect to a single database. This is what is referred to as RAC (Real Application Clusters).

A combination of a user-id and password and the objects it has created are a schema and schemas reside within the database just as do tables and indexes.

HTH

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)