Ruby on Rails

You (effectively) delete the intermediate object. You could try one of two things:

@person.pictures -= [@picture]

If all the items are persisted, then that should delete the join object immediately. (Just tested, it did work here.)

@person.pictures = @person.pictures.to_a.reject{ |p| p == @picture }

(Long-hand way to do the same thing)

Now if you have a UI around this, what you would do is build an array of checkboxes with the picture IDs in them, and then use the helper method @person.picture_ids=(array of ids) that the association built for you. You don't need to do any of the above long-hand.

So in your controller, you would add picture_ids: [] to the end of your list of allowed attributes in the strong parameters. Next, you would create a checkbox for each attached image in your form:

<%- @person.pictures.each do |picture| %>
<%= check_box_tag 'person[picture_ids][]', picture.id, true %>
<%= image_tag picture.file_url %> (just guessing how your internals look, do something here to show a thumbnail)
<%- end %>

And that should do the whole thing for you.

Walter

> On Feb 5, 2018, at 1:18 AM, fugee ohu <fuge...@gmail.com> wrote:
>
> So if @person.pictures << @picture adds a picture to a person, how do you remove a picture from a person?
>
>