class CreateHistory < ActiveRecord::Migration
  def up
    
    create_table :histories do |t|
      t.references :history_type,                       :null => false
      t.references :history_object,                     :null => false
      t.references :history_attribute,                  :null => true
      t.column :o_id,                       :integer,   :null => false
      t.column :related_o_id,               :integer,   :null => true
      t.column :related_history_object_id,  :integer,   :null => true
      t.column :id_to,                      :integer,   :null => true
      t.column :id_from,                    :integer,   :null => true
      t.column :value_from,                 :string,    :limit => 250,  :null => true
      t.column :value_to,                   :string,    :limit => 250,  :null => true
      t.column :created_by_id,              :integer,   :null => false
      t.timestamps
    end
    add_index :histories, [:o_id]
    add_index :histories, [:created_by_id]
    add_index :histories, [:created_at]
    add_index :histories, [:history_object_id]
    add_index :histories, [:history_attribute_id]
    add_index :histories, [:history_type_id]
    add_index :histories, [:id_to]
    add_index :histories, [:id_from]
    add_index :histories, [:value_from]
    add_index :histories, [:value_to]

    create_table :history_types do |t|
      t.column :name,         :string, :limit => 250,   :null => false
      t.timestamps
    end
    add_index :history_types, [:name],     :unique => true

    create_table :history_objects do |t|
      t.column :name,         :string, :limit => 250,   :null => false
      t.column :note,         :string, :limit => 250,   :null => true
      t.timestamps
    end
    add_index :history_objects, [:name],   :unique => true

    create_table :history_attributes do |t|
      t.column :name,         :string, :limit => 250,   :null => false
      t.timestamps
    end
    add_index :history_attributes, [:name],   :unique => true
  end

  def down
    drop_table :histories
    drop_table :history_attributes
    drop_table :history_objects
    drop_table :history_types
  end
end