dbTalk Databases Forums  

Very basic question

comp.databases.oracle comp.databases.oracle


Discuss Very basic question in the comp.databases.oracle forum.



Reply
 
Thread Tools Display Modes
  #1  
Old   
FC
 
Posts: n/a

Default Very basic question - 09-03-2005 , 11:21 AM






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

Reply With Quote
  #2  
Old   
Paul
 
Posts: n/a

Default Re: Very basic question - 09-03-2005 , 12:18 PM








FC <fcarpio (AT) NOJUNKcomcast (DOT) net> wrote:

Quote:
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?

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



Paul...


Quote:
FC

--

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.


Reply With Quote
  #3  
Old   
HansF
 
Posts: n/a

Default Re: Very basic question - 09-03-2005 , 01:41 PM



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 ***


Reply With Quote
  #4  
Old   
FC
 
Posts: n/a

Default Re: Very basic question - 09-03-2005 , 11:32 PM



FC wrote:
Quote:
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
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.


Reply With Quote
Reply




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off



Powered by vBulletin Version 3.5.3
Copyright ©2000 - 2012, Jelsoft Enterprises Ltd.