On Saturday, October 6, 2012 7:04:34 PM UTC+2, Marc Cooper wrote:
> I add created_at and updated_at fields to all tables via before_create and > before_update on Sequel::Model. Works great.
I assume you are using the touch plugin, since Sequel::Model doesn't support automated setting of those fields by default.
> I now have a many_to_many relationship with its associated join table. > Again this all works fine.
> However, in the case of the join table, the two *_at fields are not > touched.
> Is there a way to have these fields touched on creation and update?
There is not currently a way to do so automatically in Sequel.
Currently, the touch plugin doesn't appear to work correctly with many_*_many associations, at least on some databases. I'm considering changing the plugin so that it doesn't drop down the the dataset layer for updating associations, which it currently does for performance reasons, but which causes issues (see issue #566 on GitHub). Note that that still won't do what you want, since it wouldn't update the join table.
Personally, I recommend using database defaults for created_at columns and database triggers for updated_at columns, when possible, as they are more reliable and have fewer issues once initially setup.
Assuming you can't use a database trigger, the best way to do what you want currently is an after_save hook that updates the join table:
def after_save super DB[:join_table].where(:some_fk=>pk).update(:updated_at=>Time.now) end
On Sunday, October 14, 2012 3:42:26 AM UTC-7, Marc Cooper wrote:
> Thanks for that. Your trigger suggestions is something I'll think about.
> Actually, I'm doing the following at the moment:
> class Sequel::Model
> def before_create > return false if super == false > now = Time.now.utc > self.updated_at = now > self.created_at = now > end
> def before_update > return false if super == false > self.updated_at = Time.now.utc > end
> end
> Being part of Sequel::Model, I expected it to work on the join table, as > it does elsewhere.
The join table in a many-to-many association is not a model table. If you want similar behavior, you'll have to use a model for the join table and one_to_many association to the join table model.
