Validation doesn't work as expected for related models in Rails 4? -

i use 1 form enter data 2 models. when save parent model (tenant) child model (user) gets saved, if don't validate tenant_id in user model. if validates :tenant_id, presence: true in user model validation error "users tenant can't blank" displayed. ideas why?

tenant model:

class tenant < activerecord::base    has_many :users, dependent: :destroy, inverse_of: :tenant   accepts_nested_attributes_for :users        before_validation      self.status = 0      self.name = name_orig.upcase      email.downcase!   end    validates :name_orig, presence: true, length: { maximum: 255 }    validates :name, uniqueness: { case_sensitive: false }    valid_email_regex = /\a[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i   validates :email, presence: true, length: { maximum: 255 },                     format: { with: valid_email_regex },                     uniqueness: { case_sensitive: false }    validates :status, presence: true  end 

user model:

class user < activerecord::base    belongs_to :tenant, inverse_of: :users   validates_presence_of :tenant    before_validation      self.status = 0     self.email = email.downcase   end    valid_username_regex = /\a\w+\s?\w*\z/i   validates :name,  presence: true, length: { maximum: 50 },                     format: { with: valid_username_regex },                     uniqueness: { case_sensitive: false }    valid_email_regex = /\a[\w+\-.]+@[a-z\d\-]+(\.[a-z\d\-]+)*\.[a-z]+\z/i   validates :email, presence: true, length: { maximum: 255 },                     format: { with: valid_email_regex },                     uniqueness: { case_sensitive: false }    has_secure_password   validates :password, presence: true, length: { minimum: 6 }    validates :tenant_id, presence: true    validates :status, presence: true  end 

tenant controller:

class tenantscontroller < applicationcontroller    def new     @tenant = tenant.new     @tenant.users.build   end    def create             @tenant = tenant.new(tenant_params)     @tenant.save      if @tenant.save       flash[:success] = "welcome!"       redirect_to @tenant   # redirects tenant profile     else       render 'new'     end   end     private      def tenant_params       params.require(:tenant).permit(:name_orig, :email,           users_attributes: [:name, :email, :password, :password_confirmation])     end  end 

signup form:

<%= form_for(@tenant) |f| %>    <%= render 'shared/tenant_error_messages' %>    <%= f.label :name_orig, "company name" %>   <%= f.text_field :name_orig, class: 'form-control' %>    <%= f.label :email, "company e-mail" %>   <%= f.email_field :email, class: 'form-control' %>    <%= f.fields_for(:users) |u| %>      <%= u.label :name, "user name" %>     <%= u.text_field :name, class: 'form-control' %>      <%= u.label :email, "user e-mail" %>     <%= u.email_field :email, class: 'form-control' %>      <%= u.label :password, "password" %>     <%= u.password_field :password, class: 'form-control' %>      <%= u.label :password_confirmation, "password confirmation" %>     <%= u.password_field :password_confirmation, class: 'form-control' %>    <% end %>    <%= f.submit "save", class: "btn btn-primary" %> <% end %> 

since using nested attributes , saving both models @ same time, cannot validate tenant_id user since persisted in transaction.

because tenant not persisted, not yet have id. since not have id, there cannot tenant_id user.

in case validating tenant_id pointless, because cannot persist user without tenant since user being built on top of tenant. if user persisted, corresponding tenant present.

in case mentioned, users can sign on independent form -

to validate tenant associated in create action use:

tenant = tenant.find_by(params[:tenant_id]) user = tenant.users.build(user_params) 

instead of

user = user.new(user_params)

this way not have orphan children