Hi,
On 16/09/12 15:33, Jeroen De Dauw wrote:
Hey,
I have some questions/remarks on the "Complete Datamodel in WON" section Markus wrote up yesterday: https://meta.wikimedia.org/wiki/Wikidata/Data_model#Complete_Datamodel_in_WO...
There are several things we have not modelled yet, which I'm currently not going to comment on. For those we did already implement or thought about implementing, there are a few things that do not match what's written in this section.
SiteLanguageCode
All occurrences of this should be replaced by GlobalSiteIdentifier, as it's NOT a language code.
Yes, I wondered about this too. I will make that change soon.
ItemDescription := 'ItemDescription(' Item {TitleRecord}
[MultilingualTextValue] [MultilingualTextValue] {Statement} ')'
This is missing the aliases stuff, which would be { UserLanguageCode String }.
As explained in the text, the aliases are not distinguished from other property values in the data model right now. This was the status of the discussion when we last talked about this, but we can also re-introduce aliases as a special field (I see why this would be useful). Daniel had an argument against this, saying that many other property values could also work as aliases in certain domains (e.g. binomial names of biological species). So the special status of the alias in the data model was questioned. But the current aliases are still special in various ways (no references, no statement ranks, special UI handling, maybe special constraints [if two items have the same description, can one of them use an alias that is the title of the other?]). Discuss. ;-)
GeoCoordinatesValue := 'GeoCoordinatesValue(' decimal decimal
decimal ')'
Altitude is probably something we will not have in many cases, so I think this ought to be optional. Another optional argument would be the globe to which the coordinates belong. Different globes have different ways of measuring coordinates, so a specific set of coordinates that is valid on one might mean something else on another and simply be invalid on a third.
Yes, this DataValue is certainly in early draft stage. I will change the name as suggested by Katie. For the content, should we have optional altitude and optional planet identifier (what is the format of this? is there an IRI for Mars?)?
PropertyDescription := 'PropertyDescription(' Property
{TitleRecord} [MultilingualTextValue] [MultilingualTextValue] ')'
Right now the Property interface is very similar to the Item one, except that Item has what we're calling sitelinks (in the here discussed WON it's called TitleRecords), and property does not. That's the first difference. Copy paste error? Or am I misinterpreting the notation?
This is also based on a preliminary decision made a while back: the idea was that properties, while not having Wikipedia articles, will still need unique string identifiers that can be used in wikitext (e.g. queries) where one does not want to address properties by ID or by "label+description" pairs.
Denny mentioned that there was some discussion to use the label for this (requiring it to be globally unique for a property), so that the TitleRecord is not needed. Will this work well? After all, the label is in languages, while the TitleRecord refers to sites (which is the place where you want to refer to properties by title). Using label instead will require a more complicated site-to-language(s) mapping somehow (example: if I write a query about an Item on en.wikipedia.org, it is clear that I refer to the title of that Item in en.wikipedia.org; if I write about a Property and properties only have labels, then it is not clear if I refer to the label in en-uk, en-us, en-ca, etc.).
As with Item, it's missing the aliases.
Same answer as above. I see now that detailed explanations do not help, since nobody reads them :-p
Although we have not implemented this yet, the Entity interface implies that it contains a list of statements. I added this after some discussion with Denny. As a result, both Items and Properties have a list of statements. That's the third difference with the WON stuff. Here the question is if non-Item Entities should have statements or not. There is no consensus on this within the team yet, so I will start a new thread about it so we can discuss it in more detail.
Yes, this is easy to change. When the data model was initially discussed, there was no use case for having statements (= ranked claims with references) in properties. It seems that a property could at best have a list of PropertyValueSnaks (no auxiliary Snaks, no references, no statement rank).
Markus
Cheers
-- Jeroen De Dauw http://www.bn2vs.com Don't panic. Don't be evil. --
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