Yes, on all counts.
Although you would normally JOIN back to the SECTIONS and DIMENSIONS tables if you were using IDs as your primary and foreign keys, one of the HUGE advantages of using NATURAL KEYS (remember, that's where we started? <grin/>) is that you don't *HAVE* to do that.
SELECT sections.section, section_dimension.section
FROM sections INNER JOIN section_dimension
ON sections.section = section_dimension.section
That works, but isn't it pretty silly?
You just get the same section
value twice in each record.
So why not simply
???? It gets you the same list of section
values as the unneeded inner join gets you.
So extend the logic: When joining to section_dimension
from other tables, there is *STILL* no reason to join to sections
if all you need is the section
Once again, this is all a nice fall-out from choosing to use natural keys.
Play with it some more if you aren't convinced.