--- vladimir konrad <vk@dsl.pipex.com> wrote:
> I think that I understand basic relational theory but then I had an
> idea.
> Basically, instead of adding field to a table every time there is a
> need for it, have a table split in two: one holds identity (id) and
> one holds the attributes (linked to this id).
> Basically, if in the future user decides that the subject should
> have a new attribute, he can simply add "attribute definition" and
> attribute_definition_set (if any) and the application would handle
Basically, you would be creating your own data dictionary (i.e.
system catalog) on top of the db data dictionary. The database
already comes with a way to easily add columns: ddl. I have seen
newbie database designers reinvent this method a hundred times. The
performance hits and complexity of querying data would far out weigh
any perceived maintenance gain.
My .02.
LewisC
Lewis R Cunningham
An Expert's Guide to Oracle Technology
http://blogs.ittoolbox.com/oracle/guide/
LewisC's Random Thoughts
http://lewiscsrandomthoughts.blogspot.com/