Singleton tags?

[jducoeur]

Okay, here's a question for thought and discussion. I'm currently designing the Tag feature. Every Thing in Querki can have fields that are "tags", in the usual sense -- they contain whatever short text you would like. Tags will be hierarchical (because that is sometimes useful). And here's the interesting question: should tags *always* be multi-value?

One of the great failings of older databases is that they tend to be single-valued -- you can have only one Author for a Book, and such silliness. The real world is typically much messier, and that's reflected in the fact that most modern systems use Tags as sets of values: you can generally have any number of tags for a given item. Tags are remarkably powerful, and I expect them to be much-used in Querki.

So I'm clearly going to implement TagSet. Is there any reason to have a data type that is only a *single* Tag? The engineer in me says that of course such a thing should exist, since conceptually it's obvious, but the UX designer in me says not to, since you shouldn't expose a concept that is always a bad idea to use.

Opinions? Are there non-strawman cases where you would specifically want to only allow a single Tag on something? Or is it more bother than it's worth to expose this through the UI -- should I just have TagSet as the type that you always use?

Comments

[jducoeur]

That's possible, yes -- wouldn't be terribly hard for me to allow a meta-property that lets you say how many Tags are permitted in a given Property.

But as always, that needs to fight for its life: it's an extra complication in the UI, which I'm only going to add if it actually appears to be useful in the real world. I'm trying to be very acid about this: Querki is aimed at the general public, so my design example is Apple rather than Microsoft. Every feature has to be clearly valuable to end users before I spend pixels on it.

So the question is, how often does this happen, and how severe a problem is it when it does? I confess, I don't remember seeing it happen myself, so I suspect it's unusual.

That said, I'll add it as a possible approach. Thanks -- that viewpoint hadn't occurred to me...

[talvinm.livejournal.com]

I'll admit, I am not wed to the concept myself. It just popped into my head as a possibly useful compromise.

[jducoeur]

It is, and sorry if I came across as negative. Not sure whether it'll be worth adding or not, but it has the nice advantage that, since it is a tweak of TagSet, it could be added later, instead of being something I have to include upfront...

[talvinm.livejournal.com]

No, not overly negative. :) While not on your scale, I have written code before. I have also had to document products, trying to write the user's manual even as the product was being built, and being redesigned as it was being built. I understand and applaud the desire to avoid Feeping Creatures.