has many relation - destroy troubles

rubyonrails-talk
1

Hello, Rookie here ... learning rails and enjoying it ... having a bit-o-trouble with has many in the following scenario:

class Party < ActiveRecord::Base   has_many :target_associations, :foreign_key => 'source_party_id',                        :class_name => 'PartyAssociation',                        :dependent => :destroy

  has_many :source_associations, :foreign_key => 'target_party_id',                        :class_name => 'PartyAssociation',                        :dependent => :destroy end

class PartyAssociation < ActiveRecord::Base   belongs_to :party, :foreign_key => "source_party_id"   belongs_to :party, :foreign_key => "target_party_id" end

class CreateParties < ActiveRecord::Migration   def change     create_table :parties do |t|       t.timestamps     end   end end

class CreatePartyAssociations < ActiveRecord::Migration   def change     create_table :party_associations, :id => false do |t|       t.integer :source_party_id       t.integer :target_party_id

      t.timestamps     end   end end

This RSpec statement: it "should destroy source associations" do           @party.destroy     end

Causes this ERROR MESSAGE: ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: party_associations.: DELETE FROM "party_associations" WHERE "party_associations"."" = ?

What am I doing wrong that prevents active record from knowing how to form the delete statement?

2

Hello, Rookie here ... learning rails and enjoying it ... having a bit-o-trouble with has many in the following scenario:

class Party < ActiveRecord::Base has_many :target_associations, :foreign_key => 'source_party_id', :class_name => 'PartyAssociation', :dependent => :destroy

has_many :source_associations, :foreign_key => 'target_party_id', :class_name => 'PartyAssociation', :dependent => :destroy end

class PartyAssociation < ActiveRecord::Base belongs_to :party, :foreign_key => "source_party_id" belongs_to :party, :foreign_key => "target_party_id" end

class CreateParties < ActiveRecord::Migration def change create_table :parties do |t| t.timestamps end end end

class CreatePartyAssociations < ActiveRecord::Migration def change create_table :party_associations, :id => false do |t|

You should not have :id false, the table needs an id column. It is generally only when you use has_and_belongs_to_many that you do not require an id column

Colin

3

Uh ... ended up changing things to use the Has Many Through association ... now it all works and looks like this:

#Created a parties table class CreateParties < ActiveRecord::Migration   def change     create_table :parties do |t|       t.string :type

      t.timestamps     end   end end

#created a join table to associate one party to another class CreateAssociatedParties < ActiveRecord::Migration

  def change     create_table :associated_parties do |t|       t.integer :association_type_id       t.integer :parent_id       t.integer :child_id     end   end

end

#With a Party class like this using hmt class Party < ActiveRecord::Base

  has_many :primary_associations, :foreign_key => 'parent_id',                                   :class_name => 'AssociatedParty',                                   :dependent => :destroy   has_many :children, :through => :primary_associations

  has_many :secondary_associations, :foreign_key => 'child_id',                                     :class_name => 'AssociatedParty',                                     :dependent => :destroy   has_many :parents, :through => :secondary_associations

end

#And the join class like this class AssociatedParty < ActiveRecord::Base

  belongs_to :parent, :class_name => "Party"   belongs_to :child, :class_name => "Party"

end