"Correct" term for a 1:1 relationship between a "database" and an "instance" where > 1 such things are on the same physical server?

From: dana <dana_at_work_at_yahoo.com>
Date: Wed, 22 Jul 2009 05:24:48 -0700 (PDT)
Message-ID: <91e42049-b032-42ec-9c8f-de0d933ee133_at_w41g2000yqb.googlegroups.com>



What is the "correct" term for a 1:1 relationship between a "database" and an "instance" where there are at least two such "things" on the same physical server?

Nearly all the Oracle docs and books define a database something like the following:

DATABASE - a collection of datafiles and oracle config files; useless without an "instance" to access the database.

INSTANCE - a collection of background procs and memory structures, used to access a "database."

Where I work, people typically call each "thing" mentioned in my Subject: line an "instance" or a "database instance." What is the
"correct" term for having more than one of these "things" on the same,
unpartitioned physical server?

This may be splitting hairs; but when people don't or can't come to terms, confusion ensues--and that's typically a Bad Thing.

I noticed, or rather a colleague of mine did, that even Tom Kyte mixes terms. In the book Expert Oracle Database Architecture (2005 edition) on page 50, in the bullet-pointed definitional paragraph for Instance, he throws the word "database instance" into the mix. A "no no" according to my colleague (don't shoot the messenger, please); because the vernacular seems to be "instance" or "database instance" for the each "thing."

I like to be precise with terms, but then there are business stakeholders who use technically imprecise terms; even DBAs seem to make this mistake.

Would it be less confusing to all concerned simply refer to an "Oracle SID" to indicate a 1:1 pairing of an "instance" and a "database" where there are 2 or more of these "things" on a single, unpartitioned server?

Help! I want to "get it right" without being pedantic and trying to educate every last stakeholder in a large organization. Maybe education is the "right" thing to do, but when even DBAs use the term
"instance" incorrectly... well, that might not end well. :-)

Dana Received on Wed Jul 22 2009 - 07:24:48 CDT

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