HABTM insertion deletes old entries


#1

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.


#2

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.


#3

Scott Lillibridge wrote:

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.

It is working now.
Thank you so much Scott :slight_smile: