Source List page: Filtering by Century could be improved

[jacobdgm]

I just got an email from Debra:

A suggestion has come in that I think will improve the use of the pull-down list for century for CantusDB sources.

I'm on this page: https://cantusdatabase.org/sources/?segment=4063

Would it be possible to have "Century" just as: "9th century", "10th century", etc. up to "17th century" in the pull-down list, and then have 2 additional fields with this for one: "1st half", "2nd half", and then this for the next: "1st quarter", "2nd quarter​‌", "3rd quarter," "4th quarter." (no year dates are needed, then)

The pull-down lists will be shorter and easier to manage (see screenshot).

I know this changes the search programming, which you currently have matching all of the same century (I think) no matter which part of the century is selected. (So, this is already great, that it pulls up all sources of the same century even if some have a more detailed specification.)

Does this make it more streamlined or more difficult on the back end? For me, I can see it being more streamlined for the user, because I can specify the century if I know it, and then if I know which half I can choose that, and if I know even more I can continue to the quarter and specify that (or I can leave it blank at whatever point I am unsure). But, if it splits up the data too much and you can't attach "1st half" because it's not 'century-specific' then I understand the difficulty. In my description, above, "1st half" would be in a separate pull-down and would be applied whenever the user wanted that, based on their selection of the "century" field - but there wouldn't be a different "1st half" option for each century --- instead, just one that would rely on the previous field for context. If you know what I mean.

Also, there is a 9th and a 09th in the current list that should be cleaned up, regardless of what happens to this Century field(s).

This would be a nice thing to implement, and I can see how it would improve user experience.

This entails two main tasks:

• [x] Merging all "9th Century" sources into the "09th Century" (update: the "9th Century" was actually "9th century (875-900)" - I renamed it to "09th century (875-900)", so we haven't lost any information on which quarter-century this Century object represented)
• [ ] Adapting the Century model to allow filtering by half- and quarter-century, and update Source List page to implement this filtering.

We have options for the second of these points. I'll create a comment below this one and start recording some of the thoughts I have.

[jacobdgm]

For the Century model:

• If we wanted, we could not change the model at all, and we could just do this with pattern matching:
  • If someone wants sources from the second quarter of the 10th Century, we search for Centuries that contain 10th Century, intersection those that contain 25, intersection those that contain 50. If someone wants sources from the first half of the 11th Century, we search for Centuries that contain 11th Century, intersection those that end with 50
  • This solution depends on the names of all Centuries being entered correctly, and I foresee the code being a bit fiddly.
• We could update the Century model
  • we could give it a century property (integer: 9, 10, 11, etc.), a quarter property (optional integer: 0-3 inclusive), and a half property (optional integer: 0-1).
  • If a person is searching for a particular quarter-century, we filter by century and by quarter, and similarly for half-centuries
  • this approach is probably simplest for the time being, but less elegant than the following approach because it involves adding 3 new properties to the Century model, rather than just 2.
  • we could give it a century property, and a quarters property (set or list: one or more of {0, 1, 2, 3}). A full century will have all four possible quarters; a half-century will have two of the possible quarters, and a quarter-century will have just one.
  • If a person searches for the third quarter of the 12th Century, we filter by century == 12, and then by those centuries where quarter not in {0,1,3}.
  • If a person searches for the second half of the 13th Century, we filter by century==13 and quarter not in {0, 1} (thus also catching sources from the first and second quarters of the 13th Century too)
  • This approach could also allow us to do similar matching on Source Detail pages in a simple way, by checking for other centuries whose quarters are a sub/superset of the current century's quarters: for the "14th Century" page, we could include sources from other centuries where century == 14, and provide links to child and parent centuries, allowing users to narrow/broaden the list of sources they see.