Property talk:P301
Documentation
primary topic of the subject Wikimedia category
if [item A] has this property (category's main topic (P301)) linked to [item B],
then [item B] should also have property “topic's main category (P910)” linked to [item A]. (Help)
List of violations of this constraint: Database reports/Constraint violations/P301#inverse, SPARQL
List of violations of this constraint: Database reports/Constraint violations/P301#single best value, SPARQL
List of violations of this constraint: Database reports/Constraint violations/P301#Conflicts with P910, search, SPARQL
List of violations of this constraint: Database reports/Constraint violations/P301#Unique value, SPARQL (every item), SPARQL (by value)
List of violations of this constraint: Database reports/Constraint violations/P301#Entity types
List of violations of this constraint: Database reports/Constraint violations/P301#Scope, SPARQL
Value of category's main topic (P301) shouldn't be an instance of (P31) Wikimedia category (Q4167836) or any of its subclasses. This can happen as a result of an incorrect merge, or because a category sitelink is linked to a non-category item. In the later case, bots might change that non-category item into a category item. (Help)
Violations query:
SELECT ?item WHERE { ?item (wdt:P301/wdt:P31/wdt:P279*) wd:Q4167836 . }List of this constraint violations: Database reports/Complex constraint violations/P301#Value can't be an individual Wikimedia category item.
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This property is being used by:
Please notify projects that use this property before big changes (renaming, deletion, merge with another property, etc.) |
Discussion edit
Main article or item ? edit
Can I change main article to main item ? Q7789980 should probably have this property set to Q11703715, but it seems that there is no Wikipedia article for that. --Zolo (talk) 15:03, 21 April 2013 (UTC)
Support seems reasonable.--Stevenliuyi (talk) 07:15, 8 May 2013 (UTC)- I see that it has been changed to "main topic", that seems alright, maybe just "topic", as a category is supposed to be about just one topic ? --Zolo (talk) 08:46, 15 May 2013 (UTC)
Use for creative works edit
I would like to extend the use of this property for use with creative works. It would represent the aboutness (Q4668613) or what the main topic of a work would be. In paintings it also could be used in addition to depicts (P180). Some examples:
- The History of the Decline and Fall of the Roman Empire (Q313030) <main topic> fall of the western Roman Empire (Q689999)
- Guernica (Q175036) <main topic> Bombing of Guernica (Q170351)
--Micru (talk) 16:01, 13 June 2013 (UTC)
- Yes, there is some issue about the redundancy with P180. I suppose that we have two questions:
- Should we mix "topic of category" be mixed with "topic of creative work". The issue is that we do not want Wikipedia category to show up in normal queries, so we need to be able to segregate it. Presumable "instance of: Wikipedia category" is enough for this. We have the same kind of issue as with fictional items, so it may make sense to solve them in the same way.
- Should we have different properties for "main subject" and for "depicted in". I am not sure the difference is sufficiently clear cut to warrant different properties, but I do not see real alternatives. Possibly mark the main topics as "preferred" once it is possible ? --Zolo (talk) 07:27, 23 June 2013 (UTC)
- Regarding (1) I think we should wait for the outcome of the RfC about P107. About (2), that is hard to say... maybe depicts (P180) could be stretched? Something like "depicts/main topic"?--Micru (talk) 14:07, 6 July 2013 (UTC)
Strange property edit
The original intention was that Q subjects at Wikidata represent items, not articles. The article of certain item and the category of the same item are both related directly to the identic item. An identic item should not have two Q subjects, one for articles and second one for categories. --ŠJů (talk) 14:27, 6 August 2013 (UTC)
- You can propose this one for deletion if you wish. I am going to propose another property for the "main topic of creative work", since it would be unclear if "category items" would show up while doing searches about "main topic".--Micru (talk) 20:44, 19 August 2013 (UTC)
- ŠJů: While this is a strange topic we need it as long as we have items for Category pages. If you can persuade people to delete all the category: items then this property can follow them off of wikidata. Until then I think we need to keep it. Filceolaire (talk) 05:28, 28 August 2013 (UTC)
unknown values for category's main topic edit
soon: Basically one should be able to detect pages where the value is "unknown". Similar feature one should be able to detect "no value". לערי ריינהארט (talk) 11:00, 4 November 2013 (UTC)
template main topic edit
In the same way that Category:Syngnathiformes (Q7165189) has category's main topic (P301)=Syngnathiformes (Q650692), I think the template item Template:Taxonomy/Syngnathiformes (Q14464882) should have a statement like template main topic=Syngnathiformes (Q650692). But would it be better to rename P301 to just "main topic" so that it could be used in both cases, or are there any good reasons to use separate properties? - Soulkeeper (talk) 19:43, 30 November 2013 (UTC)
- Soulkeeper, I think that would bring confusion and it wouldn't let use the same constraints. I have started a property proposal Wikidata:Property_proposal/Generic for templates.--Micru (talk) 15:00, 23 June 2014 (UTC)
Confusion about purpose - "primary topic of the subject category" means the main thing a category is about, no? edit
Just thought I'd get something clarified since I've now edited values of this property in many items. Are these correct? In other words, do categories which refer to some facts about something else deserve to have that something else set as category's main topic (P301)? I'll list examples of where I did this:
- Category:Record labels disestablished in 1975 (Q8639489) (Created claim: category's main topic (P301): record label (Q18127))
- Category:Airliner accidents and incidents involving in-flight explosions (Q7651766) (Created claim: category's main topic (P301): aviation accident (Q744913))
- Kategorie:Datei:Logo (Rugbyverein aus England) (Q8928307) (Created claim: category's main topic (P301): rugby union (Q5849))
- ... and a few others (ctrl+f for P301)
If these are not correct, I think the documentation should be changed to make it clearer, and I'll fix my (eleven) mistakes --BurritoBazooka (talk) 21:42, 13 September 2015 (UTC)
Done I fixed them by using category combines topics (P971). Still think docs can be clearer on this property. --BurritoBazooka (talk) 04:27, 14 September 2015 (UTC)
Distinct value constraint exceptions list edit
There is a long list of exceptions listed under the distinct value constraint. I think that many of them shouldn't be there. Those exceptions might have been necessary in the past, when category's main topic (P301) was the only property that could be used to describe topics of Wikimedia category items. However, now that we also have category combines topics (P971) and category contains (P4224), that is no longer the case. Topics of category items like Category:Gymnasts by nationality (Q6970633), Category:Deep Purple songs (Q6429035) and Category:People from Płock (Q9237811) can, and are, now described using those properties. Therefore, there is no longer a need to include them as constraint exceptions in this property.
The constraint violation gadget also shows that, at the moment, the exceptions list causes a "Bad parameters" error with an explanation: "The parameters of this constraint could not be imported because they were too long.". So, it seems that the unnecessarily high number of exception parameters are already causing some problems. Additionally, because P301 is an inverse property of topic's main category (P910), every distinct value exception in P301 causes a single value exception (or inverse value exception) in P910, if they are not listed as exceptions in that P910 constraint.
If there are no objections, I would like to remove all unnecessary distinct value exceptions from this property. Starting from items that no longer use this property. --Shinnin (talk) 20:12, 18 December 2017 (UTC)
- I've now removed a number of items from the distinct value exceptions list. Here is a query that shows the remaining items that are marked as distinct value exceptions, but no longer use this property. These should probably be removed as well.
- Shinnin (talk) 15:36, 19 January 2018 (UTC)Try it!
SELECT ?item ?itemLabel ?exception ?exceptionLabel WHERE { ?item wdt:P31 wd:Q18667213; p:P2302 ?constraint. FILTER(?item = wd:P301) ?constraint ps:P2302 wd:Q21502410; pq:P2303 ?exception. FILTER NOT EXISTS { ?exception wdt:P301 ?value. } SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". } }