Allow relation options to be limited to a specific part of a note tree

[Grayda]

Let's say I have a note tree that looks like this:

root
  People
    John Smith
    Jane Smith
    Jenny Smith
  Places
    123 Fake Street
    456 Some Drive
    789 Smith Road
  Pets
    Fido Smith

People might have some attributes, like Spouse or Address, but it doesn't make sense for me to be able to pick 123 Fake Street as John Smith's spouse, so it'd be nice to be able to limit the options that appear when you start typing. Maybe something like #relation:spouse="options=25oQHIf0no8Q" where 25oQHIf0no8Q is the parent note (e.g. People) and the options available to pick from are the child notes (e.g. John Smith, Jane Smith)

There's a few benefits to this (for me, at least):

• When you start typing, you've got fewer options to pick from (so if Jane Smith is mentioned in the note about Fido Smith, it won't show up in the results). This makes picking the correct note faster and stops you from accidentally picking the wrong note
• It would remove ambiguity from a relationship, so if you have several notes called People in various parts of your tree, you'd know exactly which People you're referring to
• It could pave the way for a dropdown relation / attribute, so you'd just click the promoted attribute and it'd present all the available options to you, instead of having to remember what note you want

EDIT: And while I think about it, it'd be nice to restrict the relation search to just the title only, so if I want to add John Smith as a spouse of Jane Smith, it won't show Jenny Smith just because somewhere in that note it mentions **John Smith** is Jenny Smith's dad, so perhaps #relation:spouse="options=25oQHIf0no8Q,titleOnly" or something.

[rom1dep]

This need has been expressed several times, with different ideas floated as how to implement it, here's my take: #5089 (comment)

I think what makes it not so trivial is that some users (those keeping clean hierarchies like yourself) would prefer constraining the list of options by parent (like you suggest), and others by other means (e.g. by attribute, which would be a way to catch all the "Place" type notes in your scenario, irrespective of where they are situated in the hierarchy).

[Grayda]

I guess in those situations, one could have a #relation:spouse="options='#place'" label if that's syntactically correct, or possibly a different label just for referencing labels, like #relation:spouse="optionsLabel='place'" or something.

I guess with how big my tree is getting, even limiting it to just specific sub-notes would still take me forever to scroll through 🤣