On Thursday, July 17, 2014 11:56:57 AM UTC-7, Dan Tenenbaum wrote:
>
> Hi,
>
> I defined some hooks in Sequel::Model because I want them to be called for
> all subclasses:
>
> require 'time'
> class Sequel::Model
>
> def after_save
> super
> puts "IN AFTER_SAVE!"
> ds = DB[:timestamp]
> ds.where(true).update(:timestamp => Time.now)
> end
>
> def after_destroy
> super
> puts "IN AFTER_DESTROY!"
> ds = DB[:timestamp]
> ds.where(true).update(:timestamp => Time.now)
> end
>
> end
>
> timestamp is a table with one column (timestamp, of type Date) and one
> row. The idea is that when there is any write operation on the database
> (insert, update, delete) that's done using a model, that this timestamp is
> updated to the currrent time.
>
> The problem is, the hooks are not being called in some cases. Here's an
> example:
>
> *Status*.where(:id=>*1*).update(:status=>*"*foobar4*"*)
>
> The status table does get updated, but the timestamp table is not updated
> by this and I don't see the output of the puts() call .
>
> I can trigger the hooks if I do this:
>
> y = *Status*.new(:status=>*"*hello*"*)
>
> y.save
>
> And also (subsequently) this:
>
> y.status = *"*goodbye*"*
>
> y.save
>
> So it seems like Status.where(...).update(...) is not considered an
> operation on a model, even though it starts by invoking the model name?
>
> NB. I do have other hooks which are specific to particular models, but
> they call super and none of those are involved in this example.
>
> This is with sequel 4.9.0 and ruby 2.1.1 on Mac OS X 10.9.4.
>
This is expected behavior. You are calling Dataset#update, not
Model#update, and Dataset#update does not run model hooks. If you want to
run hooks on all affected model instances:
Status.where(...).all{|s| s.update(...)}
Note that this runs one SELECT query to get the model instances, and then
one UPDATE query for each model instance. This is different than
Dataset#update, which will only run a single UPDATE query.
If your database supports it, you are better off writing this as a trigger
instead of using a model hook.
Thanks,
Jeremy
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