In a HABTM relationship, assigning a new collection (using =) will delete
the old collection and set it to the new collection. If you want to add to a
collection, use the << operator.

On Thu, Jan 29, 2009 at 10:55 PM, Preethi Sivakumar <preethi1.s / tcs.com>wrote:

> Hi,
>
> I've 2 models Profile & User and they have HABTM relationship.
>
> ---------------------
> class Vcprofile < ActiveRecord::Base
>  has_and_belongs_to_many :users
> end
> ----------------------
> class Vcgbluser < ActiveRecord::Base
>   has_and_belongs_to_many :vcprofiles
> end
> ----------------------
>
>
> I've a screen designed in which i can assign one profile to so many
> users(through list box).
>
> Initially if i assign 2 users(say sam and rose) to the profile(say
> profile1), an entry is made into the "profiles_users" mapping table.
> -----------------------------------------------------------
> @profile.users = @User (@user is a list of users selected)
> ------------------------------------------------------------
>
> But later when i open the same page and select two more users(say jack
> and jil) for the same profile(profile1) and submit, the old two
> entries(sam and rose) are delted from the mapping table(profiles_uses)
> and these two entries are added.
>
> Why does HABTM delete the old entries(sam and rose) when a new
> assignment is made?
>
> Can anyone help?
>
> Thanks in advance.
> --
> Posted via http://www.ruby-forum.com/.
>
>