[development] One-to-one tables considered harmful

[Karthik]

> > You *completely* missed the real argument:
> >
> > Drupal is modular. Modules tend to have their own tables. Often these
> > are 1::1 tables.
>
> You misinterpreted my post. I said the 1::1 tables created by content
> types are fine. We're talking about core tables here, like
> {node_comment_statistics} that have columns often used in WHERE or ORDER
> BY criteria.

I think Earl does not want you to make any such discrimination. IMO,
you're compromising design integrity for performance. The comment
module is, whilst still a core module, an *optional* component. Some
installations/distributions might use it. Some installations might
not. Some installations might have a drop in replacement for it. For
e.g., the project module, IIRC, does not use the comment module and
still uses its own table.

I believe that Weitzman has an existing issue for this as well. There
is also another issue or mailman thread proposing that the url_aliases
table be merged into the node table for similar reasons. Let's just
invite everybody in, shall we?

How is the comment module different from other modules - core or
contrib - in similar situations? Should this (inserting/removing
fields into/from the node/taxonomy/user/x tables in .install) become
the rule of thumb to streamline any queries that result in temporary
tables?

-K