Hierarchical tags vs. own columns. Whats the difference?

[nikoski]

In the help it says:

The problem is that tags ... don’t provide a hierarchy.

http://manual.calibre-ebook.com/sub_...l#restrictions

I do not understand that. You can specify tags as hierarchical categories in the preferences the same way you can do with any own column.

What's the PROs & CONs or the essential differences between hierarchical columns and hierarchical tags?
Or in other words: what do i get more by using a hierarchical own column like "genre.x.y..." that i do not already have with a tag called "genre.x.y..."?

[chaley]

Originally Posted by nikoski

In the help it says:

http://manual.calibre-ebook.com/sub_...l#restrictions

I do not understand that. You can specify tags as hierarchical categories in the preferences the same way you can do with any own column.

What's the PROs & CONs or the essential differences between hierarchical columns and hierarchical tags?
Or in other words: what do i get more by using a hierarchical own column like "genre.x.y..." that i do not already have with a tag called "genre.x.y..."?

That sentence is saying that tags as defined by the global community are a mixed bag, not by nature hierarchical. They are words or phrases that describe something about the book, perhaps its content, perhaps it status, perhaps its source, or perhaps lots of other things. If some of those words/phrases contain periods then calibre can display those values as a hierarchy, but they will be intermixed with all the other tags with all their possibly different meanings.

Another way to say this is that there is no pre-defined base meaning for the tags category. They can be about the book, about where you bought it, about how you are managing the book in your library, and so on. If you create a new tags-like column, for example Genre, you control the meaning of the category (column), the universe of possible values, and the meanings of the individual values.

Of course you could decide that "tags" means "genre", but that could be rather difficult to enforce. Calibre creates tags for news. Downloading metadata will get you all sorts of things. And finally, that decision prevents you from using tags for things other than genre.

And of course you could do as you suggest: create a hierarchy in tags for genre using genre.x.y.z. However, that means that the outermost item conveys very little information beyond "click me to see what you really want to know."

Up to you, really.

[theducks]

fiction, science fiction, military science fiction

or
science fiction.military
Note: I drop the (IMHO) absurd tag: fiction

If you 2-click (double plus appears) you see ALL forms of Science Fiction
A singl click expands the tag and shows only those with THE base tag in the book list

[nikoski]

Thanks!

Sure, i see. Basically tags could apply to anything and are a sort of incoherent or "mixed bag" of different meanings, whereas by a column you can achieve a more specified idea already at the highest level of the hierarchy.

But to achieve a clean hierarchy within the category "Tags", separeted from the "mixed bag" of the rest of the tags, wouldn't it be similar (to a column) to create a tag called "MyTags." and create a hierarchy inside it?
I mean: instead of creating a column called "genre" i could create a tag called "-!MyTags_Genre." (to put it no top alphabetically) and tag all the items inside it the same way as in a column "genre".

Wouldn't it only "shift" the hierarchy simply 1 level deeper when compared to the same sort of hierarchy based on a column "genre"?

Or is there any "technical" point to prefer a column vs. tag for a hierarchy in terms of general usability in calibre like searching, finding, viewing the items ..., anything (except the specified meaning) essential that you get using a column, which is not possible with tags?

[chaley]

It really is up to you. If you like one scheme then use it. I prefer columns with specific meanings because it makes it easier for *me* to find and see the info, but that says nothing about what is easier for you.

However, noting your question about hierarchical tags in the CC forum, using a prefix for the hierarchy will take CC's one level. That may or may not be what you want.

[nikoski]

Ok, thanks. I was only a bit confused by the calibre help page about tags not being able to create a hierarchy, which is technically not the case.

But on the whole i think i'll better take a column as well as my hierarchical structure and maybe "series" for the magazines, especially with respect to the restricktion of only 1 level of hierarchy, as it seems, in your CC ;-)

[DaltonST]

@nikoski,

The most powerful Tag and Genre management tool in Calibre can be found at https://www.mobileread.com/forums/sho...d.php?t=247425.

See the thumbnails attached below to give you a grasp of its capabilities.

DDC is the Dewey Decimal Code and LCC is the Library of Congress Code. The Tags are in "structured English", which is in the spirit of BISAC subjects, meaning that the most general words are to the left, and the most specific to the right.

Example: Factual:History:Wars&Military-WWII-Africa-Northern Africa-Libya.



DaltonST