Re: Newbie ques: Oracle Instance

"leostar10" <leostar10_at_gmail.com> wrote:

>Hi,
> Iam new to Oracle and would appreciate any clarifications on
>these doubts I have:
>
>1. Iam reading the documentation and it says that Oracle DB Server is
>basically Oracle Database and Oracle instance. What I understand is
>there is one Oracle DB and there can be 1 or more Oracle instances. So
>my question is, when can there be more than one Oracle instances?
>
>2. Is there always a one-to-one relationship between a schema name and
>the username?
>
>3. Can the actual data corresponding to a Schema be in one datafile or
>it can be shared in more than one datafiles and also can a datafile
>contain the information pertaining to more than one schemas?
>
>Thanks!

Time to read more ( especially the Concepts manuals)...

1. search this group ( Google's advanced Group search is good for this) for DA Morgan's excellent definitions/distinctions of these
2. All schemas are based on 1 and only 1 user name each..Not all users have schema objects, however.
3. Datafiles are not involved directly, Oracle places data in Tablespaces specified by the creator of the table..These tablespaces may ( and often do) span multiple datafiles. Your concept of 'sharing' may be off..Any Schema owner ( the user that created it) may grant access to data in that schema to any other user...Does not matter where the data is physically stored.

If you are coming from another Database skill set, ( especially SqlServer) , you will be better off if you 'forget' most of the terminology/methodology you know from there - It will confuse things, especially since sqlServer uses the same terms for things and concepts that are completely different in Oracle.

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- Received on Mon Aug 01 2005 - 11:34:43 CDT