Ruby on Rails

On 2013-Aug-6, at 10:13 , masta Blasta wrote:

> selva4210@gmail.com wrote in post #1117870:
>> Hi,
>>
>> The @user object is getting saved first. That time, there is no
>> instuition membership attached to it. So one is getting created. Then
>> when you save the instuition membership again inside the controller it
>> also gets saved.
>>
>> Is this clear?
>
> You just restated what i had initially written.
>
>
> The "problem" is something to do with how rails connects newly
> initialized objects that are in memory but not yet in the database.
>
> We have built two objects like this
> u = User.new
> im = InstitutionMembership.new :user => u
>
> At that point the u (User) object doesn't know anything about the im
> object. Saving the u object does not trigger an autosave on the
> association, and the create callback creates a new membership. That's
> somewhat expected.

So tell ActiveRecord that you *want* the autosave:

class User < ActiveRecord::Base
belongs_to :account
has_many :institution_memberships, :autosave => :always
has_many :institutions, :through => :institution_memberships

after_create :set_default_membership

def set_default_membership
if institution_memberships(true).blank?
institution_memberships.create(default_data_from_account)
end
end
end

class InstitutionMembership < ActiveRecord::Base
belongs_to :user
belongs_to :institution
validates_uniqueness_of :user_id, :scope => :institution_id
end

Note the argument to 'institution_memberships(true)' which causes the memberships to be reloaded from the database.

>
> The odd issues appear after -
> u = User.new
> im = InstitutionMembership.new :user => u
> u.save
> im.save

I assume that you've simplified this so that the account_id or however the default_data_from_account manages to find the institution_id is missing.

u = User.new
u.institutions << Institution.find(somehow)

or

u = User.new
u.institution_memberships << InstitutionMembership.new(:institution_id => from_a_parameter_perhaps)

and then the u.save should do the right thing.

-Rob

>
> 'im' is aware of the user object, however it is not able to validate
> against it. When it attempts to validate, the user_id==NULL. At the very
> next log entry though, it saves itself with the correct user_id. So
> somewhere between the validate callbacks, and the create and commit
> callbacks, the 'im' object refreshed the user object and retrieved the
> user_id. Also the new_record? flag on 'im' is still set, so a new row is
> created.
>
> One of the better solutions was actually to do:
> u = User.new
> im = u.institution_memberships.build
>
> This is able to properly connect the objects in memory, and the process
> works smoothly. The association is autosaved on u.save
>
> --
> Posted via http://www.ruby-forum.com/.
>
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