On Mar 3, 2:07 pm, Thomas Gagne <tga... (AT) wide-open-west (DOT) com> wrote:
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.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.

JOG wrote:
composed of graphs of data and RDBs are two-dimensional.

What defines an account in an RDB may be composed of multiple tables.
An RDB might express multiple account types through multiple tables
where OO may reflect it as multiple classes. Attempts to make RDBs
function as graphs through mapping tools results in disappointing
performance and, in my experience, too much mapping, too much
infrastructure, and too much language/paradigm-specific layers. In
short, way more code, way more maintenance, and way more job-security
for consultants, pundits, and tool providers.


--
Visit <http://blogs.instreamco.com/anything.php> to read
my rants on technology and the finance industry. Visit
<http://tggagne.blogspot.com/> for politics, society and culture.