On Wednesday, December 12, 2018 at 5:38:29 AM UTC-8, Anthony wrote:
>
> I'm actually taking 2 values from the request as the query (q = mytable.x
>> == request.vars.X and mytable.y == request.vars.Y)
>> [X is actually not from the vars, but from the env's].
>> update_or_insert() takes care of making these more or less unique. The
>> downside of that is only knowing the id if the insert takes place, so I can
>> tell if it was an update but not where. Doing a second query is possible,
>> I admit.
>>
>
> If you need to do an update-or-insert but need the ID in case of update,
> then do not use .update_or_insert -- just write your own logic, as it is
> quite simple.
>
>
Ah, well, your answer below is way cooler and then I don't need the ID in
the calling procedure.
> a _before_update hook gives me the id, but how do I add the num_updates
>> field? lambda s, f: f.append(dict('num_updates', 2)) doesn't work
>> (gives an AttributeError). The ticket says f is really an OpRow, and
>> anyway I don't want to stick a dict *into* it. Python dict's have an
>> update method to, um, concatenate a dict to a dict; does OpRow have
>> something like that? And how can I get the present value?
>>
>
> The second argument passed to _before_update is a Row-like object of the
> fieldnames/values of the update -- so just do this:
>
> def mytable_before_update(s, f):
> # f['num_updates'] also works.
> f.num_updates = db.mytable.num_updates + 1
>
> With a lambda, you can do:
>
> lambda s, f: f.set_value('num_updates', db.mytable.num_updates + 1)
>
> Though the .set_value method is not part of the public API, so may not
> remain backward compatible.
>
> Note, you do not need the current value of num_updates -- if you use an
> expression like above, the database will do the addition for you. To see
> what the generated query looks like, try printing db(db.mytable.id ==
> some_id)._update(num_updates=db.mytable.num_updates + 1).
>
> Anthony
>
Very nice! Thanks for all the help; I am always impressed by the expertise
here.
/dps
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