Page MenuHomePhabricator

Support dates with unknown year but known month/day
Closed, DeclinedPublic


Sometimes people will give their birthday but not their year of birth. As far as I can tell, it's not possible to enter these (if it is, I haven't figured out how).

For example, the date of birth of is the 27th of August according to but no year is given. Most of the pages in ("birth year unknown") also only have the month and day.

It seems that ISO 8601 supports these by using a hyphen to represent the unknown part, e.g. --02-03 for the 3rd of February in an unknown year.

Note that this is similar to, but distinct from, recurring dates.

Event Timeline

Nikki raised the priority of this task from to Needs Triage.
Nikki updated the task description. (Show Details)
Nikki added a project: Wikidata.
Nikki subscribed.

What I forgot to mention here is that it can appear like this is already supported, because you can enter "August 24" (for the example in the description), but that actually means the year 24 AD, not the 24th day of the month. The ticket for making that more obvious is T104750.

Following a request for jawiki, there is now (birthday) with item-datatype.

While machine readability of these items could be improved, in terms of maintenance, I think it can be an advantage if this isn't combined in P569 (date of birth). Personally, I wouldn't include such dates in time-datatype properties.

Assuming this requests support for partial dates in Time values, I'm declining this for technical and semantic reasons. A Time data value represents a specific point in time (with some level of uncertainty). It doesn't represent a partial date or recurring date. Mixing partial or recurring dates with points in time would be confusing (especially for machines), they should not use the same data type nor the same properties.

If you think we need support for this kind of incomplete dates (how is this different from recurring dates?), please request a data type to be added for this. A new data type would also mean separate properties.

On that note, using P3150 for birthdays as @Esc3300 mentions, and referring to the appropriate item representing the relevant day-of-the-year, seems like a good solution to me. Is that not sufficient?