Why delete_all works but not delele(nn)?

Rails
1

Hi,

I’m sorry to post such a trivial question but…

I have a table for comments. And I can fill it normally:

@tab = Tab.find(params[:id])
@tab.comments.create(:body => ‘This is the body 1’)

I am able to correctly see their contents this way:
puts @tab.comments[0].body

I can also see its ID with:
puts @tab.comments[0].id (22 for example)

So it is fine to add rows and check the right contents.

BUT

I am able to delete all the comments with:
@tab.comments.delete_all

However I am unable to delete a row in the table…
@tab.comments.delete(22)

I’ve tried several things but as far as I know from some examples that
should work.

I’m I doing something very wrong?

Thanks once again.

2

On 6 Dec 2007, at 22:58, comopasta Gr wrote:

I am able to delete all the comments with:
@tab.comments.delete_all

However I am unable to delete a row in the table…
@tab.comments.delete(22)

On an association collection like you’ve got, delete_all deletes all
the rows in the collection, but delete deletes the object you pass in

  • it doesn’t operate on ids.
    If you want to delete a comment by id, you need to use the delete
    method on the class (ie Comment.delete 22

Fred

3

you need to use the delete method on the class (ie Comment.delete 22

Thank you so much for the explanation Fred. Indeed it worked like that.

Cheers!

4

I am able to delete all the comments with:
@tab.comments.delete_all

However I am unable to delete a row in the table…
@tab.comments.delete(22)

I’ve tried several things but as far as I know from some examples that
should work.

I’m I doing something very wrong?

Thanks once again.

Actually @tab.comments will return an array.
“delete” method is available for ruby Array class.

But there is no method called “delete_all” for Array class.

5

On 7 Dec 2007, at 12:40, Karthi kn wrote:

should work.

I’m I doing something very wrong?

Thanks once again.

Actually @tab.comments will return an array.
“delete” method is available for ruby Array class.

But there is no method called “delete_all” for Array class.

Actually it returns an AssociationProxy that’s pretending to be an
array.

Fred