[development] One-to-one tables considered harmful

[Chris Johnson]

On 6/5/07, Earnie Boyd <earnie at users.sourceforge.net> wrote:

> How is what you describe different from a child node dependent on a
> parent node?  If I have a content type relationship mapping table that
> maps a parent to a child then the children become the ``follow on''
> objects.

A comment is dependent in a modeling sense on a node.  That is, if a
comment says "Hey, I think that's a great idea" in response to an idea
posted in a blog, that comment BY ITSELF without the node makes no
sense.  It is meaningless.

One can certainly construct relationships between nodes containing
custom data which exhibit the same dependency, of not making sense
without their parent node.  Likewise, one could construct
relationships where there is no dependency, where the nodes make sense
by themselves.   That does not alter the basic fact that comments are
always dependent objects.  Most nodes today are independent objects.

Since we are trying to optimize comment behavior specifically, and
dependent data in general, it's good to keep that in mind.  Creating
dependent relationships makes it harder to optimize, especially when
selection and sorting criteria are in a joined table.