Very basic question

Hello all:
I have a very basic question about oracle database structures. I am
coming from MS SQLServer where I have three "databases", each database
has three "tables". I can access any table from any database from a SQL
connection where each database has its own connection. Once connected I
access each table from a SQL statement.

OK, now I want to recreate the same database structure in oracle. What I
do not understand is the concept of instance in oracle. Is an instance
the same as a database? Can I have several instances (databases) in
oracle and access them separately as in MS SQLServer? Or do I have to
create one database that has all my 9 tables in it?

Do you know of any on line tutorials that deal with creating multiple
databases in oracle? Any help will be greatly appreciated.

I use MS SQLServer 2k and I could use the download versions of oracle
(9i or 10g) to learn this subject.

Thanks in advance.


FC

re: Very basic question

FC <fcarpio@NOJUNKcomcast.net> wrote:
[color=blue]
> Hello all:
> I have a very basic question about oracle database structures. I am
> coming from MS SQLServer where I have three "databases", each database
> has three "tables". I can access any table from any database from a SQL
> connection where each database has its own connection. Once connected I
> access each table from a SQL statement.[/color]
[color=blue]
> OK, now I want to recreate the same database structure in oracle. What I
> do not understand is the concept of instance in oracle. Is an instance
> the same as a database? Can I have several instances (databases) in
> oracle and access them separately as in MS SQLServer? Or do I have to
> create one database that has all my 9 tables in it?[/color]


Create 3 schemas and use them like your MS SQL "databases".



Paul...

[color=blue]
> FC[/color]


--

plinehan __at__ yahoo __dot__ __com__

XP Pro, SP 2,

Oracle, 9.2.0.1.0 (Enterprise Ed.)
Interbase 6.0.1.0;

When asking database related questions, please give other posters
some clues, like operating system, version of db being used and DDL.
The exact text and/or number of error messages is useful (!= "it didn't work!").
Thanks.

Furthermore, as a courtesy to those who spend
time analysing and attempting to help, please
do not top post.

re: Very basic question

On Sat, 03 Sep 2005 12:21:38 -0400, FC interested us by writing:

Think of it this way ...

A schema is roughly the same as a SQL Server database;
A database in Oracle is the complete set of disk files;
An instance is the memory and CPU cycles needed to get at the database.

Your 'master database' is roughly the Oracle SYS schema.


PLEASE consider getting a copy of O'Reilly publishing's "Oracle
Essentials" (see http://www.oreilly.com/catalog/oressentials3/) as it will
help you get over the language hurdle. Then you can read the "Oracle
Database Concepts" manual and the "Application Developer's Guide -
Fundementals" or "Administrator's Guide" to get the details appropriate to
your job.

If developing, realize that the internals of Oracle are sufficiently
different from SQL Server that an application written for one will
rarely work well for the other - decent explanation about why and how
you need to approach Oralce development in Tom Kyte's "Effective Oracle by
Design"

--
Hans Forbrich
Canada-wide Oracle training and consulting
mailto: Fuzzy.GreyBeard_at_gmail.com
*** I no longer assist with top-posted newsgroup queries ***

re: Very basic question

FC wrote:[color=blue]
> Hello all:
> I have a very basic question about oracle database structures. I am
> coming from MS SQLServer where I have three "databases", each database
> has three "tables". I can access any table from any database from a SQL
> connection where each database has its own connection. Once connected I
> access each table from a SQL statement.
>
> OK, now I want to recreate the same database structure in oracle. What I
> do not understand is the concept of instance in oracle. Is an instance
> the same as a database? Can I have several instances (databases) in
> oracle and access them separately as in MS SQLServer? Or do I have to
> create one database that has all my 9 tables in it?
>
> Do you know of any on line tutorials that deal with creating multiple
> databases in oracle? Any help will be greatly appreciated.
>
> I use MS SQLServer 2k and I could use the download versions of oracle
> (9i or 10g) to learn this subject.
>
> Thanks in advance.
>
>
> FC[/color]

Thanks for the replies, they cleared a lot of the blur but also raised
some more questions. I hope I do not become a pest here.