Object-relational impedence
From: JOG <jog_at_cs.nott.ac.uk>
Date: Mon, 3 Mar 2008 08:52:10 -0800 (PST)
Message-ID: <0cd61579-0f26-422c-9aec-908ffdea59ff_at_i7g2000prf.googlegroups.com>
On Mar 3, 2:07 pm, Thomas Gagne <tga..._at_wide-open-west.com> wrote:
> All attempts by applications to access a DB's tables and columns
> directly violates design principles that guard against close-coupling.
> This is a basic design tenet for OO. Violating it when jumping from OO
> to RDB is, I think, the source of problem that are collectively and
> popularly referred to as the object-relational impedance mismatch.
Date: Mon, 3 Mar 2008 08:52:10 -0800 (PST)
Message-ID: <0cd61579-0f26-422c-9aec-908ffdea59ff_at_i7g2000prf.googlegroups.com>
On Mar 3, 2:07 pm, Thomas Gagne <tga..._at_wide-open-west.com> wrote:
> All attempts by applications to access a DB's tables and columns
> directly violates design principles that guard against close-coupling.
> This is a basic design tenet for OO. Violating it when jumping from OO
> to RDB is, I think, the source of problem that are collectively and
> popularly referred to as the object-relational impedance mismatch.
I wondered if we might be able to come up with some agreement on what object-relational impedence mismatch actually means. I always thought the mismatch was centred on the issue that a single object != single tuple, but it appears there may be more to it than that.
I was hoping perhaps people might be able to offer perspectives on the issues that they have encountered. One thing I would like to avoid (outside of almost flames of course), is the notion that database technology is merely a persistence layer (do people still actually think that?) - I wonder if the 'mismatch' stems from such a perspective. Received on Mon Mar 03 2008 - 17:52:10 CET