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[Bug 592599] [NEW] Hard to use exclusive queries

 

Public bug reported:

(Canonical hat on)

For Unity we want to try and group recent files into some categories
like Documents, Images, Video, Presentations, etc, and I've discovered
an unfortunate decision in our template matching algorithm, making this
quite hard to get 100% right.

The deal is that the designers think that the Documents section should
not contain Presentations (which makes quite good sense if there is a
separate section for this). Also we'd like to have an "Other" section
with unclassified stuff. But since nfo:Presentation is a subclass of
nfo:Document a query for all documents would also include all
presentations (which is "correct", but not what we want in this
particular case).

So roughly speaking the query for the Documents section should be

  all subtypes of nfo:Document but NOT nfo:Presentation

Currently this is simply not possible in Zeitgeist, because we do
logical OR between all subject templates. What I'd propose to do to make
these kind of queries possible, is to switch to logical AND between
subjects, but keep it at logical OR between events. So in code I'd like
the following code to work:

  su1 = Subject.new_for_values(interpretation=DOCUMENT)
  su2 = Subject.new_for_values(interpretation="!"+PRESENTATION)
  ev = Event()
  ev.subjects.append(su1)
  ev.subjects.append(su2)
  # now query for [ev].

As you probably realize we have the same problem (but even stronger) in
the "Other" section where we want to exclude all the listed sections and
match everything else.

** Affects: zeitgeist
     Importance: Undecided
         Status: New

-- 
Hard to use exclusive queries
https://bugs.launchpad.net/bugs/592599
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Status in Zeitgeist Framework: New

Bug description:
(Canonical hat on)

For Unity we want to try and group recent files into some categories like Documents, Images, Video, Presentations, etc, and I've discovered an unfortunate decision in our template matching algorithm, making this quite hard to get 100% right.

The deal is that the designers think that the Documents section should not contain Presentations (which makes quite good sense if there is a separate section for this). Also we'd like to have an "Other" section with unclassified stuff. But since nfo:Presentation is a subclass of nfo:Document a query for all documents would also include all presentations (which is "correct", but not what we want in this particular case).

So roughly speaking the query for the Documents section should be

  all subtypes of nfo:Document but NOT nfo:Presentation

Currently this is simply not possible in Zeitgeist, because we do logical OR between all subject templates. What I'd propose to do to make these kind of queries possible, is to switch to logical AND between subjects, but keep it at logical OR between events. So in code I'd like the following code to work:

  su1 = Subject.new_for_values(interpretation=DOCUMENT)
  su2 = Subject.new_for_values(interpretation="!"+PRESENTATION)
  ev = Event()
  ev.subjects.append(su1)
  ev.subjects.append(su2)
  # now query for [ev].

As you probably realize we have the same problem (but even stronger) in the "Other" section where we want to exclude all the listed sections and match everything else.





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