The supertitle/title/subtitle maze I got into was trying to tackle various odd situations...
In the Karyn example I posted up, there are four separate titles for the strip (even when she's not guest-starring in another title):
- Karyn, Psi, Division
- Karyn
- Karyn, Psi
- Visions
Didn't realise that about those Karyn stories (I've flicked through that era of the Meg once at best) but this is a good example.
Obviously, we can safely ignore the ludicrous idea that a bunch of stories published around the same time featuring the same character are intended to be considered as one group irrespective of whether artists stuck in different logos or editors didn't bother about standardising the strip name on the front page. With that out of the way we can get on with trying to solve the problem!
Now I see what the idea of the Supertitle is but, to me, that's introducing an imaginary element you don't really need. Like you say, in most cases it is the same as the strip title.
A couple of thoughts on how you could handle this.
[tbLinkedThrills]. A simple mapping table where you record the main strip (lets assume thats the first appearance) and any others which are a continuation. Pretty simple and you can easily query in either direction (or both.) For Karyn, it looks like this would solve the problem once you combine it with your [featuring] table.
Starts to get a bit more complicated with spin-offs and split appearance though and you might also need a [tblLinkedStories] for certain situations. Is Pussyfoot 5 really a Dredd spinoff?
[tblThrillCharacters]. Mapping table which links each strip with its central characters (various other options for relationship type, e.g. main, supporting, villain) who we can then assume are in the majority of stories and thus don't need to be explicitly in [featured]. This way you add [Character].[Karyn] for each of those Thrills and union with [featuring].[Karyn] to get all relevant stories.
This one has the benefit of allowing individual characters to spin out of one story into another. For example the structure below would be the easiest way to let you fully track Dirty Frank without confusing it with other Lowlife characters. You can easily see how the same thing will work for Shimura/Inaba/Hondo City Justice/etc.
tblThrillCharacter
LOWLIFE.NIXON
LOWLIFE.FRANK
HERSHEY.HERSHEY
HERSHEY.FRANK
featuring
TITAN.NIXON
TITAN.GERHARDT
SMALLHOUSE.FRANK
SMALLHOUSE.GERHARDT
Barney has a separate category for one-off thrills, many of which later spun out into their own series with the first installment marooned there. Not sure if that story Visions fits in there by your definition but not every story will have or need its own strip title either so there needs to be a way to handle that.
Bonus points for figuring out a way to handle a group of characters like The Dark Judges.
