Thanks for all the hard work. I am excluded from helping by lack of technical ability- though I used to be be a pretty mean Pascal and C programmer and understand the value of feedback. To cut the bs- I can help by looking at this documentation and making some naive comments. It is quicker if I am brutal!
=== Properties ===
Most information about an item is stored in the form of properties. Each property is identified by a P-number, and takes a value, which might be a time or a string or one of the limited number of other datatypes that Wikidata supports. Most often the type of value required will be another Wikidata item. So for example on d:Q2480921 (Reasonator), the property d:Property:P195 is used to identify the collection that the painting belongs to, taking the value d:Q1948674 -- the Groeningemuseum in Bruges. Together, a property-value pair is the most basic kind of statement that can be made about an item. Statements can be added either by editing an item's Wikidata page directly, or by a purpose-written bot, or using bulk tools such as QuickStatements.
This is great- no changes. But statement is not defined- and it becomes important later.
Examples of use, and details of constraints on a property, for example its required datatype, are given on the property's talk page, for example d:Property talk:P195.
I lose it here. We are flipping focus from one concept to another- to another then introducing without link . The word example is used 3 times in 3 different contexts. An alternative.
Each property has a talk page; this is used to record: Examples of use,details of constraints on a property.[a]. A specimen talk page: d:Property talk:P195
Language for describing statements. Each statement contains a property and a value, optionally with additional qualifiers. If the statement also includes one or more references, the property-value-qualifiers combination is called a claim. An item may contain several statements relating to the same property.
((Figure and caption -- see right))
If the statement also --> When the statement If has me looking for an IF_THEN_ELSE structure, when is merely an instance_of so has mental closure.
It should be noted that an item may contain more than one property-value pair for a the same property. For example an artwork may depict (P180) many things; or it may have been in different collections (P195) at different times. These can be distinguished by adding one or more qualifiers to the property-value pair.
A property may have more than one property-value pair (statement): these are controlled by using qualifiers
EachA qualifier is a property and a value that relates to the statement
(Where has the concept statement come from- do we mean )
-- for exampleTo illustrate:start date (P580) and end date (P582) could be used to add when an artwork was in a particular collection; applies to part (P518), if a statement applies to a specific tangible part of an item; or (P459) should be used if a particular determination method was used to establish the statement.
An item might also carry different property-value pairs for the same property if there werewhen there is a disagreements between different sources
-- for example, perhaps over the attribution of an artwork to a particular creator (P170).
To illustrate: An attribution issue , creator (P170).
Statements can therefore also contain references, ideally using the property stated in (P248) with the Q-number of the item for a particular article or a particular edition of a particularin a book.
Using qualifiers like volume (P478) or page (P304) or chapter (P792) or quote (P387) a for a particular article or a particular edition of a in a particular book can be stated.
It is also possible to reference bare URLs, using property reference URL (P854).
Where a statement includes references,(?) the property-item-qualifiers triple being referenced is called a claim. The diagram on the right shows the whole structure. Conflicts between statements are resolved by giving each aranking: by default statements are given a ranking of "normal"; incorrect or out-of-date statements can be marked "deprecated"; while a statement considered best can be marked "preferred".
An important property, that ought to be set for each item, is instance of (P31): this defines the item's type. This is frequently needed for constraint checks in other properties.
I think I am done. I would now consider separating out the definitions which could go into the first paragraph and the description with instances that would follow. --ClemRutter (talk) 11:50, 21 October 2014 (UTC)[reply]
Thanks, Clem, it's really great to have this feedback -- and so instantly. Your catch of my overuse of the word "example" is particularly helpful, thanks very much for this. I'm going to reformat your comment above a little, to make the quoting clearer and more consistent, then let me get back to you.
One thing I was trying to do was do "show and then explain", ie put examples up front; rather than definitions first in abstract, before the examples. But if people feel a more definition-led approach would be better, then go right ahead. Jheald (talk) 12:34, 21 October 2014 (UTC)[reply]
One clarification on the issue of referencing (see d:Help:Sources) -- it's usually not correct to reference to a book, and then specify the edition and/or the article as a qualifier to that reference. Instead the preferred approach is to create a separate item for the edition, or a separate item for the article, so that it is a Q-number for the edition or the article that is directly the value of the stated in (P248) property.
For an article, the volume number, page range, and journal name will then be properties of the dedicated item for the article, and should not be specified as qualifiers for the reference. (Though it may be appropriate to use page (P304) as a qualifier on the reference, to indicate a specific page).
I should have another go at the bit on referencing to make this clearer, because I can see my first draft was indeed confusing. I should also more strongly encourage referencing as a matter of course, not just where sources conflict. Jheald (talk) 14:04, 21 October 2014 (UTC)[reply]
An item may also carry different property-value pairs for the same property if different sources disagree -- for example, perhaps over the attribution of an artwork to a particular creator (P170). Statements should therefore also contain references. A reference is specified using a further property-value-qualifiers triple. Ideally the property stated in (P248) should be used, with the Q-number of a Wikidata item for the particular source; but it is also possible to use reference URL (P854), with a bare URL. Normally a separate item with its own Q-number should be maintained for the particular article or (for a book) the particular edition of the particular book that is the target of a reference, using the schemes at d:Help:Sources. References can be made more precise by adding qualifiers to the reference such as page (P304) or quote (P387). Qualifiers such as volume (P478) or chapter (P792) may be useful in references to a book-edition. (This information will usually already have been specified for a journal article in its item). Where a statement includes references, the property-item-qualifiers triple being referenced is called a claim. The diagram on the right shows the whole structure. Conflicts between statements can be resolved by ranking: by default statements are given a ranking of "normal"; incorrect or out-of-date statements can be marked "deprecated"; while a statement considered best can be marked "preferred".
I have also been thinking over the style points you made. But I think I do generally prefer "for example," over "to illustrate:" -- because I think it's a bit more relaxed, a bit more everyday. And I think I do still prefer "if" over "when" in the cases you picked up -- If different sources disagree / then an item may carry different property-value pairs for the same property; if the statement also includes one or more references / then the property-value-qualifiers combination is called a claim -- again, I think "if" is a bit lighter.
In section Commons-Wikidata sitelinks you say "when a reader clicks to an article, they will not automatically see a Commons category link in the sidebar, only a gallery link (if there is one)". I am confused by this statement the wikipedias I am familiar with (English and Polish) never show sidelinks from any pages to Commons, which is often quite confusing since let say Template:Authority control has sitelink to en:Template:Authority control but the only link from wikipedia to Commons is buried in See Also section and as most such links is impossible to find. So by design (a bad design IMHO) there will be no side links from Wikipedia pages to Commons.
Another drawback is that as far as I know there is no mechanism to keep all those links up to date as categories or galleries are renamed. Resulting in high chance of dead links. (or is there such mechanism?) --Jarekt (talk) 07:01, 22 October 2014 (UTC)[reply]
@Jarekt: Ooops. You're right, good catch. I was browsing with the "Other projects sidebar" beta feature enabled, so from en:Paris there's a link to c:Paris in a sidebar box "other projects" above the language links; and similarly on en:Category:Paris for me there's a link to c:Category:Paris. I hadn't realised the feature wasn't generally available yet.
(To be fair, there is a request for the sidebar to link to both Commons categories and Commons galleries, using P373/P935 for the additional links. I don't know how that is progressing. But it will not create sidebar links from Commons categories to wiki articles).
As for renaming, the process of renaming usually creates a redirect, so incoming conventional links should continue to work. I am not sure whether Wikidata sitelinks are updated to point to the renamed article -- they might be, but it's not something I personally know one way or the other. 08:40, 22 October 2014 (UTC)
I did not know about "Other projects sidebar" beta feature. It is a great improvement over current state. I would leave the sentence as is, but may be add a footnote about the beta feature. As for dead-links and redirects, I guess you are right, although I think there were people on Commons actively trying to trim number of unused redirects so they should not be relied on forever. But hey maybe someone is writing a bot for maintaining those. I do not know, so lets not worry about it at this point. --Jarekt (talk) 14:24, 22 October 2014 (UTC)[reply]
The opening sentence does not describe the fundamental purpose of Wikidata, and what is available from phase 1, but only describes what will become available from phase 2. It would be better to start out by describing Wikidata as a repository of links which can be used to link Commons pages, but not categories, to pages in all of the Wikipedias (categories can only be linked to categories). Then add the supplemental uses that can be used by the bits and pieces of other information on the Wikidata page. Delphi234 (talk) 19:37, 24 October 2014 (UTC)[reply]
@Delphi234: I don't think sitelinks are the "fundamental purpose of Wikidata". I think the fundamental purpose is to be a central structured store of information, as I have written. The page-to-page sidebar sidelinks are just what happen to have been deployed first (and I do mention them at the end of the first section). But what (IMO) is much more fundamental is the information stored on each item -- the label, the description, the statements about properties. This is what the bulk of the page describes -- what information is stored, how it is stored, how to get information in and out. IMO that is the correct focus, and the lead reflects it. (It's also the focus that is relevant for structured data, which is not going to be about sitelinks). Jheald (talk) 08:49, 25 October 2014 (UTC)[reply]
And all along I thought that sitelinks was the only purpose, and that adding properties was an afterthought. I am not sure that many items have useful properties yet. And there are tons of orphaned wikidata pages that are not linked to anything, other than one wikipedia page, and do not even have a title, let alone a description - there are existing pages they could have used but whoever created it was either too lazy or too busy to go find the correct wikidata page. Or just did not understand English or one of the other major languages enough to find the wikipedia page on the subject, and the wikidata page it used. I really wish that all of the wikis with less than 10,000 pages would have instructions to not create a wikidata link unless you were certain that one did not already exist. Delphi234 (talk) 09:08, 25 October 2014 (UTC)[reply]
Cite error: <ref> tags exist for a group named "lower-alpha", but no corresponding <references group="lower-alpha"/> tag was found
