You can have many Oracle databases on a single computer.
Limited practically by:
How fast the computer is
How many CPUs the computer has
How much memory the computer has
How much disk space the computer has
How many databases you are willing to build and maintain
In any single (1) Oracle database you can have many users.
Each of these users can have many tables. Each user may
grant or withold access to their tables from other users.
The tables for any single (1) user must each have a unique
name.
Consequently, if you have 100 users per database and two
databases on a single computer you could have 200 tables
name 'customer' on a single computer.
The above has been true since release 5 circa 1990, Oracle is
now on release 10.
>From the perspective of the DBA you can create a very complex
database situation or you can just create what you need to
successively and efficiently accomplish your mission.
Unfortunately, insecure Oracle DBAs and consultants looking
for work emblish or spin the complexity to make themselves
seem more important than they really are.
Some actually make it more complex than it needs to be
because they think it will increase their job security.
The Oracle database comes with a tool called loader which can
essentially insert any flat file into an Oracle table with
great speed. The implementation of loader can vary from
simple to very complex, the choice is yours.
Regards,
Michael Allen
[EMAIL PROTECTED]
---- Original message ----
>Date: Thu, 12 Aug 2004 09:04:57 +0200
>From: "Bengt Bredin" <[EMAIL PROTECTED]>
>Subject: SV: Witango-Talk: [ot] Databases
>To: <[EMAIL PROTECTED]>
>
> Link: File-List
>
> When we set up our database interface the goal was
> to be able to support �several databases, MSSQL,
> Pervasive.SQL, MS-Access, Oracle, Informix etc.
> We didn't supply any triggers or stored proc. But
> just to name all tables, columns, Pkey, Fkey was a
> tricky job because they all have their own
> rules for reserved names. The connection from the
> application with ODBC or ADO/OLEDB was the easy part
> of it.
> So migrate from MSSQL to something else can give you
> naming problems which will end up in editing your
> application.
> If you also use triggers and stored proc. that will
> also give you problems in converting from transact
> SQL to something else.
> Different databases have separate implementations of
> joins as well, which can give you application
> problems.
>
> As you say there are tools that can help, one can be
> data junction. I haven't tried it but I hear it's
> good, se more at
> http://www.pervasive.com/migrationtoolkit/
>
>
>
> Today we prefer MSSQL, it cost some money but the
> best thing with it today (from ver 7) is that you
> don't need any dba to handle it.
> Online backup, automatically checked integrity and
> index and scheduled jobs etc. Right set up it works
> like a charm.
> I think Oracle still need a dba to maintain the
> database. Oracle itself (as I remember ver 8) is one
> database on one computer. You only add tables to it
> so that also give you naming problems. There can
> only be one table named `customer' on one Oracle
> database. In MSSQL you just create a separate
> database
> on the same computer.
>
> I have just begin looking at MySQL and it seems to
> be an alternative if you don't require triggers or
> stored proc. Most people think it's free but that's
> only
> true if your application code is open source else
> you have to pay for the license. Ok it's cheep
> comparing to MSSQL or Oracle.
>
> So if you don't have any good reason to leave MSSQL,
> why do it ?
>
> /Bengt
>
> -----Ursprungligt meddelande-----
> Fr�n: Wilcox, Jamileh (HSC)
> [mailto:[EMAIL PROTECTED]
> Skickat: den 12 augusti 2004 00:10
> Till: [EMAIL PROTECTED]
> �mne: Witango-Talk: [ot] Databases
>
>
>
> We run all of our databases on MS-SQL2000 or MS
> Access. (I've been slowly working towards moving
> all the Access databases to SQL.)
>
> We're considering changing database servers. Under
> discussion so far are Oracle and MySQL. The campus
> has a site license for Oracle, so purchase cost
> isn't much of a factor. I've been researching MySQL
> and it looks a bit limited (no stored procs yet, no
> scheduler/jobs/etc.), but the new version due out
> next year has a several of those features added
> (although I'm not sure *when* in 2005 it'll be
> available).
>
> How difficult is it to switch to MySQL or Oracle
> from MS-SQL? I realize there will be some
> conversion issues in any db migration (i.e., SQL
> language variations, datatype variations, etc.), but
> there appear to be tools available to assist with
> that. I'm mostly concerned about the learning curve
> and how long it would take to come up to speed on a
> new db.
>
> Does anyone have experience with such a migration,
> or experience with using more than one of these
> dbs? Any info or advice would be most appreciated!
>
> Thanks.
>
> jamileh
>
>
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