[wp-hackers] hierarchical custom taxonomies vs good & old cats.

Otto otto at ottodestruct.com
Mon Dec 20 18:05:11 UTC 2010

On Mon, Dec 20, 2010 at 11:08 AM, Haluk Karamete
<halukkaramete at gmail.com> wrote:
> I will try to use you guys' ***your own words*** -  to be on the same page...
> Take a ***well defined broad cat.*** PEOPLE. Let's add sub to it. "POLITICIANS".
> That's perfect, because it is ***more specific*** than PEOPLE thus the
> reasoning for another ***well defined broad*** group under PEOPLE.
> So we got People > Politicians so far. For the same token, we can
> perfectly introduce "Movie Stars". And we all know how that would go in;
> that is another sub-cat under the "People" taxonomy, as a sibling to
> "politicians".
> So far, there is no problem in the way you guys and I would have
> wished to implement the things as.
> But we seem to be differing when we hit a rare post that talks about
> say "erdogan", The Turkish Prime Minister.
> Here I say, that "erdogan" is supposed to be a tag. You guys say, no,
> you started out as hierarchical, so you've got to keep it that way,
> thus it's got to be a cat.
> I say, yes, but how practical is it to have 100s of sub cats such as
> "obama", "blair", "bush".

Okay, the problem here is that you've gone too specific. You wouldn't
define People->Politicians->Obama in a sane taxonomy. You might define
People->Politicians, but that's as far as you'd go with it. Obama is a
specific instance, whereas your taxonomy contains things that are
broad categories (specifically, "People" and "Politicians"). Adding
"Obama" to it doesn't make any sense.

Let's say your taxonomy is "people". In that case, yes, it would
absolutely make sense to add obama to it, probably as a tag. But it
would not make sense to add "politicians" to that taxonomy.

A taxonomy is a group of like terms. And that's important: LIKE terms.
"obama" is not like "politicians", because "obama" is a specific thing
while "politicians" is a group of things.

> WHY? Because the term "obama" would have missed its context.
> Obama as what? A Politician?, A celebrity?, A Democrat?,

The problem is that you're trying to cram too much into one space. You
want your taxonomy to not only contain the terms for the specific
items, but also to contain the groupings of those items.

However, taxonomies are themselves groups of items. If you want to
define "people" and "politicians" as separate taxonomies, then you
could fit Obama into both. But it doesn't make any sense to try to fit
both groups and very specific things within those groups into the same

And the reason that this doesn't make sense is that really, what
you're doing is applying those terms to posts. A post might be about
politicians. It might be about Obama. It might also be about movie
stars. But those are not all types of people. Some of them are types
of people, and some of them are specific people.

> You guys are saying that just because I happened to choose
> hierarchial=true for that custom taxonomy, I should be stuck all the
> way down!  ; no matter how granular and how absolutely a tag-like the
> item becomes? I'm sorry, but i'm unable to comprehend the wisdom behind it.

No, we're saying that your initial choice to put two entirely
different things into the same taxonomy was incorrect in the first

Create a "people" taxonomy - non-hierarchical. Then use it to type in
the names of the people as needed.
Then, create a "people-group" taxonomy, hierarchical. Then define your
groups of people, like politicians, movie-stars, etc.

Both of them can be used to apply to your posts.

> Start out with "places" taxonomy for instance.
> And soon, you'd be introducing "museums" as a sub. and maybe another
> sub as say "churches" and then another say, "stadiums". Soon, you will
> see that this is it. You see that you are only working one level deep
> from the "places"
> top level and the "musuems", "churches", "stadiums" are all subs and all
> are siblings. Now, you know you are done as far as
> "hierarchical=true". And when you get a new post relates to a museum
> for instance, you guys and I go different routes.

Not necessarily. Your example is poor, basically, because yes, that
one has one distinct level of hierarchy imaginable to it. But not all
things or categories are the same way. It's quite possible to go from
broad to more specific without getting into single instances.

> I say, it would be easier and more meaningful to go ahead & click on
> "museums" and in the text box appearing underneath, I'd add the
> musuem's name as a tag!.

Why not create a museums taxonomy instead? Why are you making the
taxonomies themselves so broad? Places. People. I imagine you might
want to have everything under one taxonomy: Things. ;)


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