Re: understanding oracle terminology - instance, database, sid, schema
From: rogergorden_at_....gmail.com <rogergorden_at_gmail.com>
Date: Thu, 24 Jun 2010 08:41:29 -0700 (PDT)
Message-ID: <e1cb4fca-fe5e-4653-a583-c70fa2e574e8_at_i28g2000yqa.googlegroups.com>
On Jun 24, 11:24 am, The Quiet Center <thequietcen..._at_gmail.com> wrote:
> hi, I'm an open source developer who has been cast into the wide wide
> world of Oracle. As a former MySQL user mainly (no boos please :),
> there is a lot of Oracle terminology that I dont understand.
>
> Specifically:
> - instance
> - database (it appears that a single host and port can have several
> databases)
> - sid
> - schema (it appears that a single database can have several schemas
> and that a schema is a collection of tables, views, triggers, etc)
> - user (it appears that a user can have access to various schemas and
> various permissions within schemas... contrast with MySQL where there
> are only databases)
>
> Beyond definitions for the above, my goal is to ask: how do you
> uniquely identify a schema? We are running both 10g and 11g here and
> so we cannot truly refer to a schema by the name alone without
> qualifying it with the database. But since the word "instance" is
> being thrown around here as well, I have to wonder what is meant by
> that also.
>
> Thanks,
> Terrence
Date: Thu, 24 Jun 2010 08:41:29 -0700 (PDT)
Message-ID: <e1cb4fca-fe5e-4653-a583-c70fa2e574e8_at_i28g2000yqa.googlegroups.com>
On Jun 24, 11:24 am, The Quiet Center <thequietcen..._at_gmail.com> wrote:
> hi, I'm an open source developer who has been cast into the wide wide
> world of Oracle. As a former MySQL user mainly (no boos please :),
> there is a lot of Oracle terminology that I dont understand.
>
> Specifically:
> - instance
> - database (it appears that a single host and port can have several
> databases)
> - sid
> - schema (it appears that a single database can have several schemas
> and that a schema is a collection of tables, views, triggers, etc)
> - user (it appears that a user can have access to various schemas and
> various permissions within schemas... contrast with MySQL where there
> are only databases)
>
> Beyond definitions for the above, my goal is to ask: how do you
> uniquely identify a schema? We are running both 10g and 11g here and
> so we cannot truly refer to a schema by the name alone without
> qualifying it with the database. But since the word "instance" is
> being thrown around here as well, I have to wonder what is meant by
> that also.
>
> Thanks,
> Terrence
A handy conversion chart:
MySQL ORACLE Notes
instance instance/ An oracle database is simply the processes
and memory structures running on the machine, Oracle can have more
database than one database instance running on
the same machine or from the same Oracle home/version. This is also
true for
MySQL as we have both as long as
you're on a different port and socket. I've had 4 different MySQL
instances running
on the same machine.
database schema A collection of related tables/views etc.
sid A unique identifier of an instance/
database on a server DEMO and DEMO10G would be valid names for 2
different
instances. You can emulate this in
MySQL by having aliases that will connect to different MySQL instances
running on
different sockets and ports
user user a user can have access to various
schemas and various permissions within schemas in oracle. In MySQL a
user can
have access to various databases
and various permissions.
I hope that helps.
Roger Gorden Received on Thu Jun 24 2010 - 10:41:29 CDT