Hey thanks Peter!
This set me on the right track. It turned out that I ended up needing two
hidden input fields. One to specify the ID of the child object I wanted to
delete, and the other to send the '_delete' command:
<input type="hidden" value="56" name="room[bookings_attributes][][id]"/>
<input type="hidden" value="1" name="room[bookings_attributes][][_delete]"
/>
When these are parametrized, rails receives the following:
Parameters: {"commit"=>"Update Reservation!", "authenticity_token"=>"blah",
"id"=>"11", "room"=>{"bookings_attributes"=>[{"_delete"=>"1", "id"=>"56"}]}}
I was surprised to learn from some reading that setting _delete => 1 is
required because it must be set to something that evaluates to true.
And finally, the desired SQL:
DELETE FROM "bookings" WHERE "id" = 56
Thanks again. I may still end up going the ajax route, but at least now it
won't be for lack of options.
--Jon
On Mon, Nov 2, 2009 at 7:00 PM, Peter Gumeson <[email protected]> wrote:
>
> Hey Jon,
>
> It looks like you are missing the primary key of the record you are
> trying to delete. In other words, I don't think the value attribute is
> even used by rails when identifying the record to delete.
>
> I believe your input tag should look something like this:
> <input type="hidden" name="room[bookings_attributes][1][_delete]"/>
>
> (where 1 is the PK of the booking)
>
> So you'll probably have to find a way to lookup the primary key of the
> booking date that was clicked for deletion. You could print out a
> javascript hash of booking dates mapped to their PKs, and remember to
> update it whenever a booking is added/removed. Or you could do an ajax
> call to get the PK.
>
> However, keep in mind that if you're hitting the server with ajax for
> each lookup, it's probably just as easy to delete the booking while
> you're there. It always seems I run into issues like this when using
> nested attributes and usually just convert it to ajax in the end.
>
> Hope this helps.
> Peter
>
>
> On Nov 2, 7:56 am, Jonathan Christensen <[email protected]> wrote:
> > Hi all,
> >
> > This question is about getting delete to work on nested models during an
> > update on the parent object.
> >
> > I'm using a jquery datepicker to allow users to add and remove multiple
> > dates (bookings) from a parent object (room). Adding dates to the parent
> > object is easy. The jquery datepicker gives me a function that gets
> called
> > whenever the user clicks on a date. Within this function, I can build a
> > hidden input that looks like this within the page:
> >
> > <input type="hidden" value="12/04/2009" name="room
> > [bookings_attributes][][date]"/>
> >
> > Then within the controller, with the help of nested models, the call to
> > @room.update_attributes(params[:room]) knows to create the bookings as
> > well.
> >
> > My question, is how can I build an input tag in the html that will tell
> the
> > controller to remove an existing booking if the user unselects a
> previously
> > saved booking from within the calendar?
> >
> > if I build one like this:
> >
> > <input type="hidden" value="12/12/2009" name="room
> > [bookings_attributes][][_delete]"/>
> >
> > then, the parameters get passed like this:
> >
> > Parameters: {"commit"=>"Update Reservation",
> "authenticity_token"=>"blah",
> > "id"=>"11", "room"=>{"bookings_attributes"=>[{"_delete"=>"12/12/2009"}]}}
> >
> > And then the following sql happens:
> >
> > SELECT "bookings".id FROM "bookings" WHERE ("bookings"."date" IS NULL AND
> > "bookings".room_id = 11) LIMIT 1
> >
> > Which isn't right. I'm thinking maybe I need two input tags? One to
> > identify the booking that I'm removing and the other to tell the
> controller
> > to delete it? Any help on how this should work would be appreciated. I
> > could also do this the long way and just create separate and unrelated
> input
> > tags and put the intelligence for deleting into my controller, but i feel
> > like nested models should give me this for free...
> >
> > Thanks in advance,
> > --Jon
> >
>
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