south hedge
Specifically, I have a Player model with a boolean field named allow_bot_to_play_for_me. I'd like to ensure that no more than 10 Players have this field set to True.
Of course I could do this in the "save" method, but if it's possible, I'd prefer to have a constraint do this. But I can't figure out if it's possible, nor how I'd do it if so.
distant sage
Errmm... Only solution I can think of is on a trigger level.
Had been a row level check, you could've done it with a partial unique index.
south hedge
heh, I didn't mention that I'm using Postgres, but I am.
Those partial-unique indices make my brain hurt
distant sage
This looks like a cool sample to try out django-pgtriggers XD
distant sage
subtelty is not my strong suit XD
south hedge
srsly this is something I only want to do for now, to protect my server from too many clients; ideally I'll come up with a better way (like, making the server efficient enough that it can handle a lot of clients), so I don't want anything too heavy. Triggers do feel like "too heavy" 😐
distant sage
They do feel unnatural, I'd probably not use them in such a scenario as well.
south hedge
in a perfect world, I'd play with 'em to get a sense of how they work, what they're good at (and what they're not good at), &c. Always nice to have more tools in the box. Alas, the world is not perfect.
true bronze
I have found triggers to be good when calculating stuff that is effectively read only to everything else.
If they update columns that can also be updated elsewhere you can get a world of painful bugs