Comment on Use your database to power state machines
ck_@discuss.tchncs.de 1 year agoYeah, I’m wondering that too. Also, why would a transition ever be updated? Should a successful transition not be a write-once operation? I guess it boils down to the finer details of the requirements of the application.
towerful@programming.dev 1 year ago
I think the most_recent is to power the unique index constraint. This “powers” the whole thing.
Whereas the sort_order is to allow easy sorting, which is just for human readability. You could argue that you can rely on the “created_at” for this.
Considering the examples increment it by 10, I assume this is to allow admins to manually override a sequence or force a data consistency thing or whatever.
ck_@discuss.tchncs.de 1 year ago
That much is clear, the question is: why is it needed at all? The sort key has the same uniqueness constraint, so there cannot be two entries with the same sort key value. So under which circumstances does the highest sort key value not reject the most_recent transaction?
towerful@programming.dev 1 year ago
I guess separation of concerns? One is for the system, one is for display?
A unique Boolean is easier to query than sorting and limiting?
Maybe you don’t ever need the ability to display a history, but you still want the history (instead of just making the transaction_id unique constrained)?
I understand what you are saying.
Maybe that’s just how they went about it. Originally planning on using created_at to do the ordering, then later realising that a customisable sort_order is required so they can make things make sense without having to fudge timestamps.